In 899, Atenulf I of Capua conquers Benevento and unites the two duchies.

He declares them inseparable and introduces the principle of co-rule, whereby sons would be associated with their fathers, a principle soon borrowed by Salerno.

However, all Langobardia minor is unified for the last time by Duke Pandulf Ironhead, who becomes prince of Salerno in 978.

He succeeds in making Benevento an archdiocese in 969.

Before his death (March 981), he had gained from Emperor Otto I the title of Duke of Spoleto also.

However, he splits it between his sons: Landulf IV receives Benevento-Capua and Pandulf II, Salerno.

Soon, Benevento is stripped away again when Pandulf, the Ironhead's nephew, rebels, demanding his part of the inheritance.