Carolingian civil war
After Louis the Pious's death, Lothar moved immediately to disregard the division of the empire and secure for himself his father's imperial position.
The first military move of the budding civil war was Lothar's campaign that forced Louis from the Rhineland in August.
Lothar quickly reoccupied them, forcing Charles back beyond the Seine, but was unable to recreate the support in West Francia that he had formerly had.
The final negotiations, begun by 120 commissioners drawn from all sides in October, were delayed by the need to formally describe and inventory the empire.
[1] Lothar ruled the empire for the next ten months, until Louis the German rescued his father from captivity and restored him to his throne in February 834.
[6] On learning of the emperor's death, Charles sent messengers to Lothar in July to remind him of the 839 agreement and of his responsibilities as an elder brother and godfather.
When he was informed that Pippin II was preparing an assault on Bourges, he abruptly returned in time to surprise the Aquitanians and force their flight.
[16] He granted an estate at Empelde confiscated from the margrave Banzleib to the abbey of Corvey, whose abbot, Warin [de], supported him.
Lothar's Neustrian supporters, Count Gerald of Paris and Archbishop Guntbold of Rouen, made preparations to prevent his crossing by detroying bridges and boats.
[15] He sent messengers ahead, declaring that he was merely making good his rights, announcing an amnesty for all who supported him now and ordering all those loyal to Lothar to leave his kingdom.
According to Nithard, Otgar and Adalbert, who had only recently recovered from a long illness, nursed a personal hatred of Louis and wished to see him dead.
Lothar then returned across the Rhine, leaving Adalbert in charge with the title of dux (commander) of Austrasia and ordering him to take oaths from the east Frankish nobility.
[22] On 13 April, Charles the Bald left Sens intending to ambush Gerald and Guntbold in the Forest of Othe [fr].
Louis's intention was probably to dissipate Adalbert's army in many separate river crossings, leaving him vulnerable to an ambush while buying himself time.
[27] They offered Lothar a division of the empire that would have given him Franconia west of the Rhine and the land between the Charbonnière Forest (roughly the river Scheldt) and the Meuse.
[29] Pippin arrived at Fontenoy on 24 June and Lothar restated his claim to the undivided empire, rejecting Charles and Louis's ultimatum.
[33][34] Charles chased Pippin towards Aquitaine before breaking off and turning north to occupy Paris, Soissons and Reims, forcing Ebbo into exile.
[36] Leaving Otgar of Mainz to guard the Rhine against a crossing by Louis, he turned west and marched to the Seine, forcing Charles to retreat to Saint-Cloud on the left bank.
[34][36] Nithard says that Lothar's army included Saxons, Alemans and Austrasians, indicating that he still had significant support east of the Rhine.
[38] He "spent the whole winter in wasted effort", per the Annales Fuldenses, trying to reconstruct his network of support in Neustria, Brittany and Aquitaine.
[43] In late March 842, Louis and Charles held an assembly at Aachen, incorrectly believing that Lothar had fled to Italy.
[44][45] The assembled bishops, accusing Lothar of lacking "the knowledge of how to govern the state" and having fled "first from the battle-field and then from his own realm",[45] turned to the victorious brothers to "admonish, ask, and command you to receive the kingdom and rule it according to God's will".
[44] In answer to the bishops, who were acting in any case under their direction, the two kings divided the empire north of the Alps to the exclusion of Lothar.
[52] Louis marched to Saxony where the Saxons peasants, calling themselves Stellinga ('comrades in arms'), had renounced Christianity and "rose up violently against their lords", in the words of the Annales Xantenses.
Lothar had offered to respect the rebels' traditional rights and customs, but this had merely pushed the Saxon nobility and church towards Louis.
According to the Annales Bertiniani, in the summer of 842, Louis "captured all the leaders of that unholy scheme", "punished 140 of them with beheading, hung fourteen on the gallows" and completely put an end to the Stellinga.
The 120 commissioners eventually relocated to Koblenz, meeting by day in the basilica of Saint Castor and spending the nights on opposite sides of the Rhine to prevent outbreaks of violence.
[51] Louis and Charles soon requested a delay in the proceedings so that they could make a detailed description of the empire, since they lacked complete knowledge of royal resources.
Charles and Louis sent envoys to Lothar at Thionville, where it was agreed that a formal description of the empire be made and the division determined on that basis.
[55] The description—the Latin word is descriptio—would have been produced by missi (envoys) sent throughout the empire to describe and inventory bishoprics, monasteries, royal palaces, manors, benefices and markets.
