LOUIS II, King of Italy, Roman Emperor. — Son of Emperor Lothair I, born around 820 near Brescia on 12 August 875. In 844 his father sent him to Italy, assisted by his great-uncle Bishop Drogo of Metz, with the title of King of the Lombards: he was tasked with reasserting imperial authority, especially in Rome, against the popes and the local aristocracy, and with defending the peninsula against the persistent threat of Arab invasions. After asserting his authority in Pavia, he proceeded to Rome: there he compelled Pope Stephen IV and the Roman people to swear loyalty to the emperor; he was consecrated and crowned King of Italy by the Pope. On this occasion, the Prince of Salerno, Siconulf, paid him homage. He then established himself in the Italian capital, Pavia, but the worsening Arab threat forced him to return to France to arrange for important armaments.
The expedition organized in the following years succeeded in repelling the Saracens threatening Benevento; however, Bari and Taranto remained firmly in enemy hands. Pope Leo IV himself took part in a campaign in 849 to drive the Saracens from Ostia. Louis managed to arrange the two principalities of Salerno and Benevento to serve as bulwarks. Returning to Rome in the spring of 850, Louis was crowned emperor by Leo IV at his father’s behest, and in the following years he governed Italy as his father’s colleague but in his own name. Assemblies of bishops and counts enabled him to assess the condition of the kingdom and address the needs of administration; his marriage to an Italian noblewoman, Ermengard, integrated him more fully into the life of the country. In accordance with Lothair’s instructions, he consistently monitored the papal curia, overseeing the elections of Benedict III and Nicholas I. After his father’s death in 855, he remained sole emperor, but he failed to obtain an equitable distribution of the domains from his brothers or to impose his authority upon them. Only Lothair II ceded to him in 859 the bishoprics of Geneva, Lausanne, and Sion in exchange for his support in Lothair’s marital dispute with the pope; upon the death of his other brother, Charles, in 862, he took part in the division of the domains, occupying Arles, Embrun, and Grenoble. In the marital affair of his brother Lothair, Louis first tried to compel Pope Nicholas I—even by force—to uphold Lothair’s claims for separation from his lawful wife, but later reconciled with the pope and contented himself with attempting a peaceful settlement. The Saracen threat compelled him to mount another major expedition to Apulia in 866, and he then sought the alliance of the Byzantine emperor, though negotiations for a marital agreement came to nothing. In 859 Louis managed to wrest Bari from the Arabs, but an uprising in Benevento immobilized him; taken prisoner, he regained his freedom on condition that he never return. He obtained from the pope release from the oath imposed upon him, and in 872 he was again crowned in Rome.