Which duke of Benevento offered fealty to Charlemagne?

Arechis was the duke of Benevento who offered fealty to Charlemagne. In 787, Charlemagne marched into southern Italy to bring Benevento under Frankish supremacy. Arechis withdrew to the fortified coastal stronghold of Salerno, where he negotiated rather than risk the destruction of his principality.

The settlement required Arechis and his subjects to swear loyalty, pay tribute, and provide hostages, including his son Grimoald. Charlemagne accepted the submission while leaving Benevento under its own ruler. The arrangement therefore represented overlordship rather than the complete annexation of the southern Lombard territory.

Arechis had earlier resisted Charlemagne's authority. After the Lombard kingdom in northern Italy fell in 774, he adopted the title prince of Benevento, a political statement that emphasized the principality's independence. His submission in 787 was consequently a strategic concession, not a lasting surrender of local autonomy.

A common mix-up is confusing Arechis with Grimoald, his son and hostage. Grimoald later ruled Benevento after Arechis died, but it was Arechis who personally offered fealty to Charlemagne.