Fact-checked by Grok 2 weeks ago

Lothair I

Lothair I (c. 795 – 29 September 855) was a and king whose reign marked a pivotal phase in the fragmentation of the . As the eldest son of I the Pious and , he was designated successor and crowned co- in 817 at , assuming sub-kingships in (815–817) and (from 822, formally crowned king by in 823). Lothair's rule was defined by familial conflicts and imperial divisions, including revolts against his father in 830 and 833, where he temporarily deposed Louis at the Field of Lies. Following Louis's death in 840, Lothair engaged in civil war with his brothers and , culminating in the in 843, which allotted him the central strip of the empire—Middle Francia—encompassing , , , and , while retaining the imperial title. In 852, Lothair anointed his son Louis II as co-emperor, but facing health decline, he retired to Prüm Abbey as a and partitioned his among his sons shortly before his death there. His inheritance arrangements accelerated the Carolingian Empire's dissolution into distinct kingdoms, laying groundwork for medieval Europe's political map.

Origins and Early Career

Birth and Family Background

Lothair I was born in 795, though the exact location and date within the year remain uncertain in contemporary records. He was the eldest surviving son of , who would succeed as emperor of the in 814, and , a noblewoman from the region whose father, Ingerman, held the title of there. As a member of the , Lothair's lineage traced directly to through his paternal grandfather, positioning him as a key heir in the expansive Frankish empire that spanned much of . His mother Ermengarde bore several children before her death in 818, including Lothair's full brothers Pepin (born c. 797, later king of ) and (born 806, later king of , known as ). A half-brother, (born 823), emerged from the Pious's second marriage to Judith of , which would later complicate dynastic successions. This family structure, rooted in strategic alliances and imperial expansion under , underscored the Carolingians' emphasis on dividing realms among male heirs to maintain control amid growing centrifugal pressures.

Association as Co-Emperor and King of Italy

In July 817, Emperor convened an at where he crowned his eldest surviving son, Lothair, as co-emperor, marking the formal association of Lothair in imperial rule. This event coincided with the issuance of the Ordinatio Imperii, a that designated Lothair as the principal heir to the imperial title and supreme overlord over the empire's sub-kingdoms, while allocating him core territories including , parts of , and . The younger brothers, Pepin (king of Aquitaine) and (king of Bavaria), were confirmed in their holdings as subordinates to Lothair, aiming to preserve dynastic unity under a single imperial authority despite the division of realms. The Ordinatio initially reaffirmed , Louis's nephew, as , but Bernard's rebellion against the succession plan—launched in response to his exclusion from further —led to his , blinding, and in 818. With Italy's throne vacant, transferred the kingdom to Lothair later that year, effectively merging it with his co-emperor's responsibilities and extending his authority southward. This succession addressed immediate instability in , where Bernard's supporters had challenged central control, but it also positioned Lothair to manage the region's semi-autonomous nobility and papal relations. Lothair first exercised governance over Italy from 822, traveling there to assert authority amid ongoing administrative challenges. On 5 April 823, crowned him king in , a that reinforced Carolingian legitimacy through papal and symbolized the intertwining of imperial and kingship. This , distinct from his earlier imperial elevation, highlighted the papacy's role in legitimizing rule over , where the of traditionally marked kingship, though specific details of its use in 823 remain unrecorded in primary accounts. The event also prompted Lothair to issue privileges to the Church, fostering alliances crucial for maintaining order in a kingdom prone to factionalism.

Dynastic Conflicts with Louis the Pious

Revolt of 830

In early 830, Lothair I, alongside his full brothers Pepin I of Aquitaine and Louis the German, launched a revolt against their father, Emperor Louis the Pious, driven by opposition to the emperor's favoritism toward his younger son Charles (later known as Charles the Bald), born to second wife Judith of Bavaria. This stemmed from Louis's recent grants of territories, such as Alemannia, to Charles at the expense of the elder sons' established subkingdoms, contravening the Ordinatio Imperii of 817 which had divided the realm among Lothair, Pepin, and Louis the German. The brothers, supported by elements of the Frankish nobility and clergy resentful of Judith's influence, mobilized armies and advanced on the imperial court. By March 830, the rebels captured Louis the Pious at Compiègne, northwest of Paris, where he was residing during a campaign against Breton insurgents. The emperor was compelled to affirm Lothair's seniority as co-emperor and revert to the 817 constitutional arrangements, effectively sidelining Charles and Judith, who faced temporary exile to religious confinement. Lothair assumed de facto control in the north, while his brothers secured their respective regions, marking a brief triumph that highlighted the fragility of Carolingian succession norms reliant on paternal authority rather than automatic primogeniture. Rebel cohesion eroded amid reports of Lothair's harsh measures against perceived loyalists, alienating key supporters. At the assembly of in October 830, Louis rallied Austrasian and forces, prompting the sons' submission; Lothair and his brothers publicly repented and restored their father to power. A follow-up assembly at in February 831 confirmed Louis's authority, stripping Lothair of the imperial title (relegating him to ) and reintegrating into the succession plans, though without a full subkingdom. The episode exposed underlying tensions over imperial unity versus divisional inheritance but ultimately reinforced Louis's rule temporarily, as no permanent territorial changes resulted from the uprising.

Revolt of 833 and Temporary Deposition

In early 833, , and co-emperor, allied with his full brothers and against their father, Emperor , amid ongoing grievances over the latter's favoritism toward his young son Charles (later known as ) and perceived mismanagement of imperial divisions established in 829. , viewing his imperial rights as threatened, took the lead in the rebellion, garnering support from disaffected Frankish nobles, bishops such as Agobard of , and crucially , whom had independently confirmed in office earlier that year without Louis's consent. This papal endorsement lent ecclesiastical legitimacy to the uprising, framing it as a correction of Louis's alleged moral failings and tyrannical rule. On June 30, 833, advanced to confront the rebels on a plain in known as Rothfeld (later dubbed the Lügenfeld or Field of Lies due to the perceived treachery), near , intending to negotiate a settlement with Lothair. Instead, upon sighting the among the opposing forces and facing a larger coalition, much of Louis's army defected overnight, leaving him isolated with his wife Judith and ; the brothers then seized him without battle upon his crossing to their camp. Lothair assumed effective control, proclaiming himself sole and confining Louis under guard. The rebels convened an assembly at in early October 833, where on October 1 was compelled to perform public penance at the Basilica of Saint-Médard, stripping off , confessing to sins including neglect of duty and unjust rule, and submitting to deposition as and . Bishops, led by those aligned with the rebels, issued the Relatio Compendiensis, justifying the act as necessary imperial correction while treating as a monk-like figure; redistributed territories, granting to Pepin, to , and portions to under guardianship, while retaining and the imperial title. This deposition lasted only until March 834, when shifting loyalties among nobles and 's overreach prompted 's restoration at Saint-Denis, but the 833 revolt marked a pivotal humiliation, exposing fractures in Carolingian unity.

Reconciliation and Restoration

In the aftermath of the Field of Lies on 30 June 833, where Emperor was deposed and confined to the monastery of Saint-Médard at , Lothair's assumption of sole imperial authority alienated his brothers and . The brothers, fearing Lothair's dominance and rallying former supporters of their father, mobilized armies and advanced on in early 834, liberating Louis from custody by . Lothair, unable to confront the combined forces effectively, retreated southward to , where his loyalists provided refuge but limited his influence beyond the . Louis the Pious, restored to provisional authority, convened an assembly at the Abbey of Saint-Denis near on 1 March 834 (or possibly 30 March per some accounts), where he underwent a ceremonial reinstatement as , absolved by bishops including those who had previously supported the deposition. This event marked a pivotal and political reversal, with Louis leveraging assemblies and oaths of fidelity to rebuild his network among the Frankish and . Lothair, confronting isolation and the risk of total dispossession, dispatched envoys and ultimately submitted without battle, acknowledging his father's superior claim. Reconciliation was formalized through family councils in 834, restoring Lothair to his prior titles as co-emperor and while subordinating him to Louis's oversight. Assemblies such as the one at later that year reaffirmed core elements of the 817 Ordinatio Imperii, preserving Lothair's Italian realm and imperial dignity but curtailing his ambitions for unified control. This fragile accord, however, sowed seeds for ongoing tensions, as Louis adjusted sub-kingdom boundaries to accommodate his youngest son , prompting Lothair's intermittent resistance thereafter.

Struggle for Supremacy After 840

Outbreak of Civil War

Following the death of Emperor on 20 June 840 at Ingelheim, Lothair I, his eldest surviving son and co-emperor since 817, received the imperial insignia and promptly claimed sovereignty over the entire Carolingian , overriding the outlined in his father's final ordonnance of 839, which had allocated specific kingdoms to each son. Lothair's assertion rested on the Ordinatio imperii of 817, which had designated him as the primary heir to the imperial dignity with overarching authority over his brothers' sub-kingdoms, a framework he viewed as enduring despite subsequent modifications by Louis. This claim positioned Lothair not merely as and the Middle Frankish territories but as supreme ruler entitled to tribute and obedience from in the East and in the West, while also drawing support from Pepin II, the rebellious king of . Lothair's brothers rejected this interpretation, interpreting Louis's 839 division—East Francia to Louis, West Francia to Charles, and a central belt including Italy and the imperial title to Lothair—as the binding inheritance, thereby denying Lothair any feudal overlordship. In response, and forged a defensive in July 840, meeting at to coordinate resistance and pledging mutual aid against Lothair's ambitions. On 24 July 840, Lothair escalated tensions by formally proclaiming his imperium at , allying explicitly with Pepin II and mobilizing an army northward from toward , the traditional imperial capital, with the intent to enforce submission through military pressure. Initial hostilities erupted in late summer 840 as Lothair's forces, numbering several thousand including and contingents, conducted raids into West Frankish territories around the and rivers, seizing plunder and compelling local loyalties while avoiding direct engagement with the allied armies of his brothers. and , in turn, raised levies and fortified key positions, with repelling incursions near and securing the eastern frontiers; these skirmishes, marked by devastation of crops and villages, disrupted trade and estates without decisive outcomes, setting the stage for prolonged attrition. The brothers' alliance was further solidified by the Oath of Strasbourg in 842, sworn in Romance and Germanic tongues to symbolize their unified front against fraternal overreach, though the war's opening phase from 840 to early 841 remained characterized by maneuver and proxy violence rather than pitched battles.

Battle of Fontenoy and Defeat

Following the death of Emperor Louis the Pious on June 20, 840, Lothair I, as the eldest son and co-emperor, asserted claims to overlordship over the entire Carolingian inheritance, prompting his brothers Louis the German and Charles the Bald to form an alliance against him. Lothair in turn allied with his nephew Pepin II, claimant to Aquitaine, drawing support from Burgundian and Italian contingents to bolster his numerically superior but less cohesive forces. Initial skirmishes and raids characterized the civil war's early phase, but by early 841, the opposing armies converged in the region south of Auxerre, setting the stage for a pitched confrontation viewed as divine judgment on the fraternal dispute. The Battle of Fontenoy-en-Puisaye unfolded on June 25, 841, approximately 22 miles south of in present-day , involving tens of thousands of combatants in what contemporaries described as unprecedented carnage among the . Lothair and Pepin II's coalition, including heavy shield walls reinforced by Burgundian barons such as Ermenaud III of , initially held strong defensive positions and repelled early assaults from Charles's troops under Guerin. Fighting commenced around 6 a.m. with volleys of throwing axes shattering shields, followed by brutal hand-to-hand clashes; by midday, however, coordinated charges led by and reinforcements from Bernard of Septimania's forces broke Lothair's lines, turning the engagement into a . Lothair personally fought with gallantry alongside Pepin II but could not stem the collapse, as allied momentum overwhelmed his flanks. Casualties were catastrophic, with estimates ranging from 25,000 to dead—predominantly from Lothair's side—marking the bloodiest conflict of the Carolingian era and decimating the Frankish nobility. The Annals of recount an "countless number" slain, with the slain left unburied in places due to the scale of slaughter, underscoring the battle's brutality as a judgment exposing the folly of fraternal division. Lothair retreated in disarray to , abandoning his camp and treasures to the victors, while and divided their spoils before parting ways. This defeat shattered Lothair's ambitions for unified imperial rule, forcing him into a defensive posture and paving the way for prolonged negotiations that culminated in the in 843. Pepin II's position in weakened irreparably, ceding effective control to by perceived divine sanction, while the battle's trauma highlighted the empire's fragility amid divided loyalties and logistical strains on large feudal levies. Lothair retained nominal emperorship but lost practical supremacy in , retreating focus to and amid ongoing instability.

Treaty of Verdun and Division of the Empire

Following the in June 841 and the subsequent Strasbourg Oaths of February 842, which formalized the alliance between and against Lothair I, prolonged negotiations ensued to partition the and avert further conflict. These talks, mediated partly by church officials and local assemblies, culminated in the , agreed upon in August 843 at Verdun-sur-Meuse. The divided the empire into three kingdoms, with Lothair I receiving the central belt designated as (or in its northern extent), encompassing territories from in the north through the , , the west of the , , , and extending south to the , which he had ruled since 817. This allocation included key imperial sites like and retained for Lothair the title of emperor with nominal overlordship over the other rulers, reflecting his status as the eldest surviving son of . obtained , comprising lands east of the including , Alemannia, and , forming the core of future German territories. was allotted , the western regions beyond the , , , and rivers, laying groundwork for modern . The division was pragmatic rather than strictly ethnic or linguistic, following natural barriers like rivers but resulting in an elongated, heterogeneous prone to internal divisions and external pressures. For Lothair, this realm's fragmentation—spanning diverse regions with weak central cohesion—complicated governance, as it lacked unified loyalties and faced immediate challenges from rebellious vassals and the ambitions of his brothers. The treaty temporarily stabilized the empire but accelerated its disintegration, with 's later subdivisions under the in 855 and in 870 underscoring the unsustainability of Lothair's inheritance.

Rule Over Middle Francia and Italy

Administrative Challenges and Instability

Lothair's Middle Frankish realm, allocated by the Treaty of Verdun in 843, encompassed a discontinuous north-south corridor from Frisia to central Italy, rendering centralized administration logistically arduous due to poor communications and vast distances that impeded swift military or judicial responses. To mitigate these issues, he devolved powers early, installing his son Louis II as sub-king of Italy in 844 and elevating him to co-emperor in 850, while local counts retained substantial autonomy in regions like Provence and Burgundy. Despite promulgating capitularies—such as the 823 provisions adapting Roman law to Lombard customs in Italy—these measures struggled against entrenched local interests and fiscal decentralization, where magnates increasingly evaded royal oversight. External pressures intensified instability: fleets from Aghlabid raided on 28 August 846, desecrating and plundering the extramural basilicas of St. Peter and St. Paul before withdrawing with captives and treasure, exposing vulnerabilities in southern defenses despite Lothair dispatching Louis II with reinforcements too late to engage. Concurrently, Viking incursions escalated from 845, with fleets annually targeting Low Country coasts and riverine accesses in Lothair's northern territories, straining resources already committed to Italian fronts. Internally, defiance from provincial elites erupted, exemplified by the 845 rebellion in orchestrated by Fulcrad of Arles, who rallied local counts against imperial exactions; Lothair personally led forces to crush it, coercing Fulcrad's submission before redirecting him against the Saracens. Such uprisings underscored the fragility of loyalty among frontier aristocrats, whose semi-independent power bases prioritized regional defense over obedience to a distant sovereign, foreshadowing the realm's partition at Lothair's death in 855.

Continued Fraternal Rivalries

Despite the divisions formalized by the on 11 August 843, which allocated to Lothair I while granting to and to , fraternal tensions endured over territorial control and imperial precedence. Lothair's retention of the imperial title fueled resentment, as his brothers resisted any subordination, leading to opportunistic alliances and incursions that undermined the treaty's stability. In 844, Lothair allied with to counter a in led by the sons of his deceased brother Pepin I, successfully reasserting control over the rebellious claimants but highlighting the interconnected vulnerabilities of their realms. This cooperation proved temporary, as underlying rivalries prompted to invade Charles the Bald's West Frankish territories in 845, sacking and extracting tribute, an action that indirectly pressured Lothair's borders by destabilizing the western frontier. By 849, Lothair actively joined in a campaign against , with their combined forces attacking to exploit Charles's internal weaknesses and expand influence, though the incursion yielded limited gains and reinforced the pattern of shifting loyalties among the siblings. These maneuvers exemplified the causal fragility of the post-Verdun order, where personal ambitions and regional disputes perpetuated conflict until Lothair's death in 855, preventing any lasting fraternal concord.

Internal Divisions and Grants to Sons

, Lothair I's inheritance from the in 843, encompassed a fragmented strip of territory stretching from the to , lacking natural geographic cohesion and marked by diverse ethnic groups, linguistic barriers, and competing local loyalties that fueled internal instability. These divisions manifested in frequent revolts by nobles and cities, particularly in and the , where Lothair struggled to enforce authority amid ongoing threats from Saracens in the south and in the north. To address succession and mitigate fragmentation, Lothair began granting territories to his sons during his lifetime. In 844, he designated his eldest son, II, as , associating him in rule to secure the peninsula's governance while Lothair focused on northern affairs; was later crowned co-emperor in around 850. This early devolution reflected Lothair's recognition of Italy's administrative burdens but also sowed seeds of divided loyalties, as increasingly acted independently. Facing terminal illness in 855, Lothair formalized the partition at the on 19 , abdicating and dividing among his three surviving sons to preserve Carolingian control over the imperial legacy. Louis II inherited along with the imperial title and oversight of the three realms; received the northern core known as , spanning , the valley, , and up to the ; obtained the southern domains of , including coastal regions and parts of . Lothair then retired to Prüm Abbey as a , dying ten days later on 29 855. This tripartite division exacerbated internal fractures, as the sub-kingdoms remained economically interdependent yet politically rivalrous, with and soon contested by uncles and , leading to rapid absorption and the effective dissolution of Middle Francia's unity. The grants prioritized dynastic continuity over territorial viability, contributing to the Carolingian Empire's centrifugal disintegration.

Ecclesiastical and Imperial Relations

Alliances with the Papacy

Lothair I's imperial authority was reinforced through ceremonial and diplomatic ties with the papacy, beginning with his as co-emperor by on Easter Sunday, April 5, 823, in in . This act, following his designation as co-emperor by his father in 817, underscored the papacy's traditional role in anointing Carolingian rulers, thereby lending ecclesiastical legitimacy to Lothair's governance over and his broader imperial claims. The death of Paschal I in 824 and the subsequent election of Eugene II amid Roman factional violence prompted Lothair to assert oversight, dispatching envoys who compelled to swear to the . On November 11, 824, Lothair promulgated the Constitutio Romana in concert with Eugene II, stipulating that papal candidates must pledge loyalty to the Frankish , undergo examination for , and secure before consecration to curb electoral abuses and ensure stability. This pact delineated mutual obligations, with the guaranteeing protection against external threats and internal disorder in exchange for papal deference in temporal affairs, marking a structured that peaked Frankish influence over processes without fully subordinating the spiritual domain. Tensions resurfaced in January 844 upon the disputed election and rapid consecration of without notifying Lothair, violating the Constitutio Romana. Lothair responded by sending his son Louis II at the head of an army to , but Sergius, despite physical frailty from , intercepted the forces at to negotiate reconciliation, averting invasion. On June 6, 844, Sergius crowned Louis II as in St. Peter's, restoring amity and affirming Lothair's dynastic control while securing papal endorsement against rival claimants and amid escalating raids on coasts. Under (elected 847), Lothair sustained protective alliances, dispatching forces in 846 to counter incursions that sacked parts of and its environs, including the basilicas of St. Peter and St. Paul. These efforts, coordinated with papal fortifications and indulgences for defenders, exemplified the emperor's role as secular guardian of the , though operational leadership increasingly devolved to Louis II; Lothair's confirmations of Leo's privileges further cemented this partnership until his death in 855.

Policies on Church and Imperial Authority

Lothair I asserted imperial authority over matters in line with Carolingian precedents, viewing the as the protector and overseer of the while subordinating papal and episcopal actions to royal oversight. In November 824, following the death of and the election of Eugene II amid factional strife, Lothair promulgated the Constitutio Romana, a nine-article negotiated with the new pope and nobility. This decree required imperial missi to oversee papal elections, ensuring their confirmation by the , and mandated that the pope-elect swear an oath of fidelity and subjection to the before consecration. It safeguarded the rights of all under papal and imperial protection, confirmed the pope's primacy over Western bishops, and prohibited the alienation of papal patrimony without imperial consent, thereby reserving ultimate sovereignty in to Lothair as and co-. This policy stemmed from Lothair's direct governance of Italy since 822 and his re-coronation as emperor by on April 5, 823, which reinforced the symbiotic yet hierarchical Frankish-papal alliance established under . By intervening in the 824 papal crisis—sending troops to depose the briefly elected Zinzinnus (or John) and install Eugene II—Lothair demonstrated practical enforcement of imperial rights over Roman affairs, preventing unchecked papal autonomy that could undermine Carolingian influence. The Constitutio thus codified a framework where ecclesiastical legitimacy depended on imperial validation, reflecting Lothair's broader strategy to integrate church structures into his administrative control amid and Byzantine threats in . Throughout his reign, Lothair extended this approach by appointing loyal bishops and abbots to key sees in and , leveraging ecclesiastical networks for political stability and revenue, as seen in his grants of royal immunity to monasteries conditional on fidelity oaths. He co-convoked synods with his father , such as the 829 Frankish assemblies issuing the Religiosam vitam reforms on clerical discipline and regular diocesan synods, which Lothair upheld in his territories to enforce liturgical and standards under . However, fraternal wars and regional revolts limited consistent implementation, with Lothair occasionally conceding to papal mediation—such as Gregory IV's role in the 833 deposition of —to bolster his claims, revealing pragmatic tensions between asserted authority and diplomatic necessity.

Final Years, Death, and Succession

Later Campaigns and Health Decline

In the mid-840s, Lothair faced escalating threats from raids in , culminating in the on 27 August 846, during which invaders plundered and other churches. In response, Lothair suppressed a related rebellion in led by Count Fulrad of and personally joined an expedition against the Saracens, aiming to restore order and protect papal territories, though the campaign yielded limited decisive victories amid ongoing instability. These efforts highlighted the persistent vulnerability of his Italian domains to Muslim incursions from bases in and coastal enclaves, straining resources already divided by fraternal conflicts. By 851, Lothair undertook another journey to Italy to address Lombard infighting and indirect pressures, convening the rival princes Radelchis I of and Siconulf of at to enforce a of their territories and renew oaths of , thereby seeking to consolidate Frankish overlordship in the south without major pitched battles. This diplomatic-military intervention, supported by his son Louis II's subsequent enforcements, temporarily stabilized the region but underscored Lothair's reliance on intermittent personal oversight rather than sustained conquest, as Viking raids in the north further diverted attention and manpower. Lothair's health deteriorated sharply in 855, prompting his amid a serious, unspecified illness that left him despairing of recovery. On 23 September, he formally divided among his sons—Louis II receiving and imperial title, the northern lands, and —before retiring to Prüm Abbey, where he died on 29 September. This rapid succession of events reflected the physical toll of decades of civil strife and defensive warfare on the aging , whose realm fragmented further upon his passing.

Death and Partition of Territories

In September 855, Lothair I, afflicted by a severe illness while campaigning against Saracens in , abdicated the throne and convened his sons at his palace in Attigny to arrange the division of . On 19 September, the formalized the partition among his three surviving sons: the eldest, Louis II, inherited the Kingdom of along with the imperial title and authority over the associated territories; Lothair II received the northern region known as , encompassing areas between the , , and rivers extending to the ; and the youngest, Charles, was granted the southern Kingdom of , including and lands bordering the Mediterranean. This subdivision adhered to Carolingian customs but exacerbated the empire's fragmentation, creating unstable buffer states vulnerable to absorption by neighboring realms. Following the treaty, Lothair retired to the Abbey of Prüm on 23 September, where he died on 29 September 855 at age 60. He was buried at the abbey, with his tomb enduring as one of the earliest preserved Carolingian imperial monuments. The partitions immediately sparked disputes, as Lothair II's Lotharingia faced claims from his uncles Louis the German and Charles the Bald, leading to further treaties like Meerssen in 870 that redistributed much of the territory.

Family

Marriage and Immediate Kin

Lothair I was born circa 795 as the eldest son of Emperor Louis I the Pious (d. 840) and his first wife, (d. 818), daughter of Ingerman, count of . His full siblings included Pepin I (d. 838), who was designated king of , and Louis (d. 876), later styled as ruler of the East Frankish Kingdom. Lothair's position as firstborn positioned him as co-emperor with his father from 817, amid ongoing familial divisions over imperial succession. In October 821, Lothair married Ermengarde (d. 851), daughter of Hugh, count of , at . This alliance linked the Carolingian imperial line to the prominent Tours comital family, enhancing Lothair's regional influence in Francia Media. Ermengarde served as empress consort until her death on 20 March 851, predeceasing Lothair by four years.

Children and Dynastic Outcomes

Lothair I and his wife had at least ten children, including five sons and five daughters, though some died in infancy or youth without significant political roles. The surviving sons—Louis II, , and —were designated as heirs to his territories in , as established by the on 19 September 855, just days before his death. This agreement allocated , along with the imperial dignity, to Louis II (born circa 825, died 875); the northern region, later termed , to (born circa 835, died 869); and the southern territories of , , and parts of to (born circa 845, died 863). The daughters played roles in forging alliances through marriage: Hiltrude (circa 826–865) wed Berengar, count of , strengthening ties in ; Gisela (born after 830, died after 861) married Eberhard I, of , linking the Carolingians to Friulian nobility; and Bertha (died 852) married Adalard, , though her line produced no major dynastic heirs. Other daughters, such as Ermengarde and Gisela (distinct from the Friuli spouse), entered religious life or had limited documented impact. These unions aimed to secure loyalty among regional elites but did not prevent the erosion of central authority. Dynastically, the division accelerated the Carolingian empire's fragmentation, as each son's realm proved unstable. Louis II's inheritance preserved Carolingian imperial claims in until his death without male heirs in 875, after which his uncle briefly assumed the title before its lapse into contention. 's , lacking strong defenses, fell into dispute between his uncles and following his childless death in 869, culminating in the (870), which split it between East and West . Charles's premature death in 863 without issue prompted an immediate partition of between his brothers, with Louis II absorbing the core while gained peripheral areas, further diluting Lothair I's Middle Frankish construct. These outcomes underscored the pitfalls of , contributing to the devolution of unified Carolingian rule into enduring regional kingdoms by the late ninth century.

Legacy

Short-Term Consequences of Divisions

The in 843 temporarily halted the civil war among Lothair I, , and , but the allocation of to Lothair proved unsustainable due to its elongated geography spanning from the to , encompassing linguistically and culturally diverse regions that hindered unified governance. This division weakened imperial cohesion, as Lothair's realm lacked defensible natural boundaries and faced internal dissent, prompting ongoing skirmishes with his uncles over border territories in the 840s and 850s. Lothair I's illness in 855 led to his abdication and the on 23 September, partitioning among his sons: Louis II inherited with the imperial title, received the northern Lotharingian territories (including modern , , and ), and obtained the southeastern lands. These smaller polities inherited the vulnerabilities of , with fragmented authority enabling intensified Viking raids along the northern coasts—such as the 855 sack of —and Saracen incursions in , which Charles struggled to repel due to limited resources. The partitions fostered immediate rivalries, as East and West Francia eyed Lotharingia's fertile lands; following Lothair II's death in 869 without legitimate heirs, and divided it via the in 870, absorbing much of it and further eroding any remnant of a centralized Middle Frankish entity. This rapid reconfiguration underscored the short-term consequence of diminished Frankish unity, shifting power dynamics toward bilateral conflicts between the western and eastern kingdoms while exposing divided territories to opportunistic invasions and local power vacuums.

Long-Term Impact on European Political Geography

The Treaty of Verdun, signed on 10 August 843, partitioned the Carolingian Empire among Lothair I, Louis the German, and Charles the Bald, creating Middle Francia under Lothair I that stretched from the North Sea coast through the Low Countries, along the Rhine and Moselle valleys, Burgundy, Provence, and into northern Italy. This division established enduring geopolitical fault lines, with West Francia evolving into the Kingdom of France and East Francia forming the basis of the East Frankish Realm, precursor to the Holy Roman Empire and modern Germany. Middle Francia, however, proved geographically and culturally fragmented, lacking cohesive linguistic or ethnic unity, which accelerated its subdivision and absorption into neighboring realms. Following Lothair I's death on 29 September 855, the further divided among his three sons: Louis II received and the imperial title along with , Lothair II inherited the northern Lotharingian strip encompassing modern-day , , , , and parts of , while Charles acquired the southern region. The instability of led to its partition after Lothair II's death in 869 via the in 870, splitting it between East and and solidifying the as a boundary between emerging and German spheres. This fragmentation prevented the persistence of a central imperial entity, fostering the development of distinct nation-states and regional principalities in the and that influenced the political geography of medieval and . Over the subsequent centuries, the divisions contributed to the linguistic and cultural divergence between Romance-speaking and Germanic eastern regions, with contested borderlands like remaining flashpoints in Franco-German conflicts into the . The absence of a viable underscored the challenges of maintaining trans-regional authority, paving the way for feudal fragmentation and the rise of hereditary monarchies centered on natural geographic units rather than the expansive Carolingian model. These partitions thus marked the inception of 's multipolar political landscape, where developed as a separate entity and the emerged as a contested between major powers.

Scholarly Assessments of Lothair's Ambitions and Failures

Scholars evaluate Lothair I's core ambition as upholding the imperial hierarchy defined in the Ordinatio Imperii of 817, which enshrined his status as co-emperor and overlord of his brothers' realms, reflecting a commitment to dynastic legitimacy and centralized authority over the Carolingian inheritance. This vision prioritized the emperor's symbolic and practical primacy, as evidenced by the consistent invocation of imperial titles in his charters during the of 840–843, which framed his claims against and as defenses of rightful order rather than mere territorial aggrandizement. However, Lothair's inflexible insistence on this framework eroded support from Frankish magnates, precipitating the fratricidal conflict after Louis the Pious's death on September 20, 840, and his military defeat at the on June 25, 841, where allied forces under his brothers inflicted heavy casualties on his army. The ensuing on August 10, 843, compelled him to accept —a fragmented corridor from to —highlighting the practical failure of his strategy, as the territory's elongated shape hindered effective defense against Viking raids and internal dissent while diluting imperial cohesion. Lothair's later actions compounded these shortcomings: his abdication and division of among his sons via the on August 1, 855—assigning to Louis II, to , and to —exacerbated fragmentation, leaving no viable core for unified rule and inviting opportunistic seizures by relatives. Historians attribute this to a causal mismatch between Lothair's ideological rigidity and the pragmatic demands of Carolingian politics, where fraternal alliances and elite consent proved more decisive than titular supremacy, ultimately hastening the empire's devolution into rival kingdoms. Revisionist assessments, such as that in Maria Schäpers's monograph, counter traditional portrayals of Lothair as inept or overly pious to a fault, emphasizing his competent in during the 820s–830s and strategic delegation to Louis II, while rejecting claims of his instigation or mishandling of the 830 revolt against . Yet, even these views acknowledge source limitations rendering Lothair a somewhat opaque figure, with scant evidence of innovative policies in or to offset the structural vulnerabilities his partitions entrenched. Overall, scholarly consensus holds that Lothair's emperorship, though marked by conventional Carolingian virtues like monastic piety in his final retreat to Prüm Abbey, failed to adapt to kin rivalries, yielding a of division over durable unity.

References

  1. [1]
    Lothair I, Emperor
    Date of Death: 28 or 29 September 855. Place of Death: Prüm monastery in Ardennes (also buried there). His date of death is given as 28 September 855 by Annales ...Missing: evidence | Show results with:evidence
  2. [2]
    20.06.12 Schäpers, Lothar I. (795-855) und das Frankenreich
    Lothair I not only served as sub-king in Bavaria and Italy, the latter throughout the 820s and 830s, he also held office as co-emperor under Louis the Pious ...
  3. [3]
    Lothair der Franken (c.795 - 855) - Genealogy - Geni
    Jan 28, 2024 · Lothair was the eldest son of the Carolingian emperor Louis the Pious and his wife Ermengarde of Hesbaye, daughter of Ingerman, duke of Hesbaye.Missing: biography | Show results with:biography
  4. [4]
    Lothair I OF ITALY (795-855) - RootsWeb
    Lothair was the eldest son of the Carolingian emperor Louis the Pious and his wife Ermengarde of Hesbaye, daughter of Ingerman the duke of Hesbaye. On ...
  5. [5]
    Lothair (Carolingian) Italia (0795-0855) | WikiTree FREE Family Tree
    "Holy Roman emperor (840-55), and eldest son of Holy Roman Emperor Louis I, the Pious, and grandson of Charlemagne. Lothair became co-ruler with his father in ...
  6. [6]
    The Troubled Reign of Louis the Pious, Emperor of the Holy Roman ...
    Dec 3, 2018 · Lothair became co-emperor with his father, while Pepin and Louis became king of Aquitaine and Bavaria respectively. The sons of Lothair, Pepin, ...
  7. [7]
  8. [8]
    The Cardinals of the Holy Roman Church - Biographical Dictionary
    ... Lothair was hailed as Augustus by the Roman people. The pope declared that from that moment Lothair had power over the Roman people. Lothair immediately ...
  9. [9]
    CAROLINGIANS - Foundation for Medieval Genealogy
    However, Emperor Louis reasserted his authority at the assemblies of Nijmegen in Oct 830 and Aix-la-Chapelle in Feb 831, depriving Lothaire of the imperial ...Missing: Lothair | Show results with:Lothair
  10. [10]
    [PDF] "Playing the Tyrant in Gaul": Carolingian Discourse on Kingship and ...
    Nithard asserts that Lothar instigated a revolt against Louis the Pious in 830 as a response to Louis giving Alemannia to Charles, Lothar's half-brother.
  11. [11]
    law, politics and the theory of empire in the early ninth century
    In 830 Louis' sons and many other influential persons, both clerical and lay, had risen against Louis. The excesses Of Louis' wife, Judith, and of his chief ...
  12. [12]
    LOTHARINGIA, KINGS & DUKES
    Lothaire and his brothers rebelled in Mar 830, captured their ... However, Emperor Louis reasserted his authority at the assemblies of Nijmegen in Oct 830 ...Missing: Lothair | Show results with:Lothair
  13. [13]
    Louis the Pious and the contours of empire - Wiley Online Library
    Jul 7, 2014 · As it turned out, the revolt of Pippin and of Louis's other sons against their father in the spring of 830 forestalled any Frankish campaigns at ...
  14. [14]
    The Field of Lies Louis I (the Pious) [813-840] - Heritage History
    Louis soon found that he was a prisoner. From that day this bloodless battlefield was no longer called the Field of Blood, but the Lugenfeld or Field of Lies.
  15. [15]
    The Public Penance of Louis the Pious - Medievalists.net
    Jun 21, 2012 · ... penance of Emperor Louis the Pious in October, 833. Composed by an anonymous bishop on behalf of his episcopal peers as their collective ...Missing: deposition date
  16. [16]
    What Happened in June 833 AD - On This Day
    The Field of Lies. Jun 30 "The Field of Lies": Louis the Pious, King of the Franks is tricked and forced to abdicate by his three sons and Pope Gregory IV ...
  17. [17]
  18. [18]
    First proofs of Past Convictions: The Penance of Louis the Pious and ...
    But by February 834, Lothar's brothers Pippin and Louis the German had turned on him and with their armies marched on Aachen to free their captive father ...
  19. [19]
    [PDF] The Reinstatement of Emperor Louis the Pious at St. Denis (1st of ...
    The Reinstatement of Emperor Louis the Pious at St. Denis ... church dignitaries who had sealed his deposition on the “Field of Lies” (833) through the.
  20. [20]
    [PDF] Military History in East Francia under King Louis the German (c. 825 ...
    ... Lothar's men were encamped. This time, Louis the Pious was successful in reconciling his son to him; Lothar could not profitably offer battle to his father ...Missing: Lothair | Show results with:Lothair
  21. [21]
  22. [22]
    HIST 210 - Lecture 21 - Crisis of the Carolingians - Open Yale Courses
    In this lecture, Professor Freedman discusses the crisis and decline of Charlemagne's empire. Increasingly faced with external threats – particularly the ...Missing: assembly Lothair
  23. [23]
    Carolingian Civil War: The Battle of Fontenoy, June 25, 841
    Jun 25, 2023 · Lothair and Pepin initiated battle and took the upper hand until the arrival of Guerin and his army of Provençals. While Pepin and his ...
  24. [24]
    Civil War | European Royal History
    On July 24, 840 in Strasbourg, Lothair precipitated a new civil war by declaring his imperium over all the lands of the empire and, joining with his nephew ...
  25. [25]
    The Battle of Fontenay in 841 - De Re Militari
    In June 841, the two sides fought an indecisive battle at Fontenay. Two years later, the Treaty of Verdun partitioned the kingdom into three states, one for ...
  26. [26]
    Battle of Fontenoy June 25, 841 - War History
    **Summary of the Battle of Fontenoy, June 25, 841:**
  27. [27]
    Treaty of Verdun | Research Starters - EBSCO
    The Treaty of Verdun, enacted in 843, marked a significant turning point in early European history by partitioning the Carolingian Empire among the three sons ...Missing: primary | Show results with:primary
  28. [28]
    A document of partition: how to cope with the Treaty of Verdun (843)
    Nov 13, 2008 · The Treaty laid the foundations for the division of France and Germany. This is half-true. It's true, in as much as West and East Francia are meaningful ...
  29. [29]
    Division of the Carolingian Empire in 843 & 870 CE
    Apr 18, 2021 · The Treaty of Verdun in 843 CE partitioned the Kingdom of the Franks into West Francia (green), East Francia (orange), and Middle Francia ( ...
  30. [30]
    [PDF] Shadow Kingdom: Lotharingia and the Frankish World, c.850-c.1050
    These potent royal sites were a major reason why control of Lotharingia became such a driving ambition for the kings of east and west Francia after the middle ...
  31. [31]
    [PDF] Roman Law in the regnum Italiae under the Emperor Lothar I (817 ...
    Interestingly, Lothar I, as ruler of the kingdom of Italy, issued a capitulary provision addressing this problem as early as 823:Missing: Lothair | Show results with:Lothair
  32. [32]
    Lothair I, Medieval Emperor | Encyclopedia.com
    Lothair I, Medieval Emperor, Reigned: 817–855. b. 795. The oldest son of Emperor Louis the Pious and a key figure, with his brothers, in the civil wars.Missing: evidence | Show results with:evidence
  33. [33]
    Lotharingia: Europe's Forgotten Country | by Grant Piper - Medium
    May 6, 2024 · Lothair I was the king of Middle Francia, which unsurprisingly, was sandwiched between West Francia and East Francia. All three kingdoms were ...
  34. [34]
    Fall of the Carolingian Empire | Short history website
    Apr 10, 2018 · In 855 within Treaty of Prüm, Lothair I divided the kingdom between his three sons. The oldest son Louis II (“the Younger”) received Italy ...<|separator|>
  35. [35]
    Louis Ii | Encyclopedia.com
    Aug 8, 2016 · In 844, Lothair I designated him king of Italy and in 850 he was crowned emperor of the West in Rome.Missing: grant date
  36. [36]
    Treaty of Prüm | alasnme.com - alasnome.com
    As Lothair I nears death, he abdicates and sub-divides his third of Francia - Middle Francia, among his three sons. He died 10 days later. Prüm. Lattitude: ...Missing: 848 | Show results with:848
  37. [37]
  38. [38]
    CATHOLIC ENCYCLOPEDIA: Pope Sergius II - New Advent
    As Sergius was, after a disputed election, consecrated without any reference to the Emperor Lothaire, the latter was indignant, and sent his son Louis with ...
  39. [39]
    CATHOLIC ENCYCLOPEDIA: Pope Eugene II - New Advent
    A concordat or constitution was then agreed upon between the pope and the emperor (824). The "Constitutio Romana", in nine articles, was drawn up seemingly ...
  40. [40]
    The Cardinals of the Holy Roman Church - Biographical Dictionary
    The Constitutio Romana of 824 was composed of nine items and affirmed that the rights of all persons under the protection of the emperor and the pope were ...
  41. [41]
    [PDF] Church property and the Carolingian political order in the last years ...
    This dissertation is set within the reign of Louis the Pious, emperor of the Carolingian empire from. 814 to 840, and focusses specifically on the ...
  42. [42]
  43. [43]
    Lothar I | Holy Roman Emperor & German King | Britannica
    Sep 25, 2025 · The eldest son of the emperor Louis I the Pious and a grandson of Charlemagne, Lothar was made king in Bavaria after Louis succeeded Charlemagne ...
  44. [44]
    Lothair I | Historica Wiki - Fandom
    Lothair I (795 – 29 September 855) was the Holy Roman Emperor from 817 until his abdication in 855. He was also King of Italy from 818 and King of Middle ...
  45. [45]
    August 8, 870: The Treaty of Mersen | European Royal History
    Aug 8, 2023 · The treaty followed an earlier treaty of Prüm which had split Middle Francia between Lothair I's sons after his death in 855.
  46. [46]
    Ermengarde de Tours (800 - 851) - Genealogy - Geni
    In the middle of October 821 in Diedenhofen (Thionville), she married the Carolingian Emperor Lothair I (795-855). In 849, two years before her death, she ...
  47. [47]
  48. [48]
    855: M. Francia divides
    The division of Middle Francia in 855 CE had profound consequences for European history: - Political Fragmentation: The Carolingian Empire continued to fracture ...
  49. [49]
    [PDF] CAROLINGIAN IMPERIAL AUTHORITY - MOspace Home
    The Carolingians were able to wield great ideological and unifying power through their implementation of the imperial title, and through the person of Lothar, ...Missing: Lothair | Show results with:Lothair
  50. [50]
    [PDF] Carolingian War and Violence and the Course of Medieval History
    The relatively short-lived. Carolingian Empire indeed left long-lived consequences in the form of Europeanization, specifically with the Treaty of. Verdun ...
  51. [51]
    Treaty of Verdun | Carolingian Empire, Charlemagne, Louis the ...
    Treaty of Verdun, (August 843), treaty partitioning the Carolingian empire among the three surviving sons of the emperor Louis I (the Pious).Missing: Lothair | Show results with:Lothair
  52. [52]
  53. [53]
    Francia Media | historical region, Europe | Britannica
    After Louis's death (840) open warfare broke out; Louis's third son, Louis the German, allied with Charles in attacking the eldest son, the emperor Lothar I.
  54. [54]
    [PDF] The Fall of the Carolingian Empire
    The legacy of the Treaty of Verdun would prove to have lasting consequences for over a millennium. The partition of Charlemagne's empire by his three grandsons ...Missing: term effects
  55. [55]
    Lotharingia, East and West Francia – 843-1100
    The already vulnerable position of the Middle Kingdom was further weakened when Lothar I died in 855 and the kingdom, at the Treaty of Prüm, was divided under ...Missing: instability | Show results with:instability
  56. [56]
    The importance of the emperor: Lothar I and the Frankish civil war ...
    Apr 28, 2004 · Lothar I's perspective on the Frankish civil war has not previously been explored. Close analysis of the distribution and wording of the most significant body ...