What royal title did Charlemagne take after conquering the Lombards?

Charlemagne took the title King of the Lombards after conquering the Lombard kingdom in 774. The title reflected his defeat of Desiderius, the last Lombard king, after a prolonged Frankish siege of Pavia in northern Italy.

Charlemagne's campaign began after Pope Adrian I appealed for Frankish help against Lombard pressure on papal territories. Once Pavia surrendered, Desiderius was removed from power and sent into exile. Rather than merely ruling Lombard lands as a Frankish monarch, Charlemagne adopted the Lombard royal title itself, creating a personal union between the Frankish and Lombard kingdoms.

This title is sometimes confused with King of Italy. “King of Italy” became a later and broader designation, while Charlemagne's contemporary title was specifically King of the Lombards. He retained Lombard laws and institutions but gradually reorganized the kingdom through Frankish-style counts. His son Pepin later became king of the Lombards in 781.