The Landulfids or Atenulfings were a noble family of Lombardic origin in the ninth through eleventh centuries. They were descended from Landulf I of Capua, whose own ancestry is unknown and who died in 843. The dynasty produced a line of princes which ruled most of southern Italy at one time or another and even one pope, Victor III.
In 839, a civil war broke out in the Principality of Benevento. Landulf of Capua supported Siconulf in the war and when the Emperor Louis II forced a division of the principality on the claimants in 849, Capua was assigned to the Principality of Salerno. But Landulf's heirs aimed to make themselves independent of any princely authority. By 860–861 this task was essentially complete and Capua was independent county.