Which southern Italian duchy did Charlemagne march into in 786?

Charlemagne marched into the southern Italian Duchy of Benevento in 786.

Benevento was a Lombard duchy that survived after Charlemagne conquered the Lombard kingdom in northern Italy in 774. Its ruler, Duke Arechis II, governed a powerful and relatively independent state based in southern Italy. Charlemagne’s expedition aimed to extend Frankish influence over the region and prevent Benevento from becoming a center of resistance.

Charlemagne arrived in Italy toward the end of 786. Arechis avoided a direct confrontation by retreating to the fortified city of Salerno, then negotiated with the Frankish king. He acknowledged Charlemagne’s authority, offered hostages, and sent his son Grimoald as part of the settlement.

The arrangement proved unstable. After Charlemagne left, Arechis sought Byzantine support and explored cooperation with opponents of Frankish rule. The crisis continued after Arechis’s death, and Benevento retained considerable autonomy for much of the Carolingian period. Naples was another southern Italian power, while Friuli and Spoleto were separate Italian duchies involved in different episodes of Charlemagne’s expansion.