Lothair I

Lothair I was born in 795, the eldest son of the Carolingian emperor Louis the Pious and his first wife, Ermengarde of Hesbaye, and thus a grandson of Charlemagne. From an early age he was marked out for the imperial succession. In 815 he was sent to govern Bavaria, and in 817 Louis issued the Ordinatio Imperii, which made Lothair co-emperor and assigned him the largest share of the realm, while his brothers Pepin of Aquitaine and Louis the German received subordinate kingdoms. After the failed revolt of Bernard of Italy in 817–818, Italy was placed under Lothair’s authority. He spent much of the following years in the peninsula. In 823 Pope Paschal I crowned him emperor at Rome. In 824 he promulgated the Constitutio Romana, which asserted imperial oversight of the papacy and required a newly elected pope to swear fidelity to the emperor before consecration.

The birth of Charles, later known as Charles the Bald, to Louis the Pious and his second wife Judith of Bavaria upset the settlement of 817. Lothair opposed the creation of a kingdom for his half-brother and twice joined his full brothers in revolt. In 830 the emperor was briefly deprived of power; in 833, at the Field of Lies near Colmar, Louis was abandoned by his troops, deposed, and made to perform public penance, while Lothair took control of the government. Support for the old emperor revived, the brothers quarrelled, and Louis was restored. Tension continued until Louis the Pious died in June 840. Lothair then claimed supremacy over the whole empire as emperor, but Louis the German and Charles the Bald refused to accept his overlordship.

War followed. On 25 June 841 the armies met at Fontenoy-en-Puisaye, where Lothair and his nephew Pepin II of Aquitaine were defeated with great slaughter. In 842 Louis and Charles bound themselves by the Oaths of Strasbourg. Lothair was compelled to negotiate, and in August 843 the Treaty of Verdun divided the Carolingian Empire. Lothair kept the imperial title and received Middle Francia, a strip of lands from the Frisian coast and the Low Countries through the Meuse and Rhine valleys, Burgundy and Provence, to the kingdom of Italy, including the traditional imperial residences of Aachen and Rome. The arrangement left him with a long, heterogeneous territory that was difficult to defend and administer.

In 821 Lothair had married Ermengarde of Tours, daughter of Hugh, count of Tours. The marriage produced several children who survived to adulthood, among them Louis II, who was associated in the empire and in Italy; Lothair II; and Charles of Provence, as well as daughters who entered religious life or dynastic marriages. Ermengarde died in 851. In 855, seriously ill, Lothair partitioned Middle Francia among his three sons at Prüm: Louis II received Italy and the imperial title, Lothair II the northern territories that came to be called Lotharingia, and Charles the south-eastern lands of Provence. He then laid down his crown, received the monastic tonsure at the Benedictine abbey of Prüm, and died there on 29 September 855. He was buried in the abbey church. His middle kingdom fragmented within a generation, but his name remained attached to Lotharingia, the region between France and Germany.