Atenulf made his son, Landulf III, co-prince. Together they made alliances with the local Greek states, such as Naples and Gaeta. After Atenulf died, Landulf mostly continued the policies of his father. He is best known for his involvement at the Battle of Garigliano, in which the Fatimid Saracens were defeated. He spent most of his reign after Garigliano trying to weaken the Byzantine authority in Apulia and the Campania. His son, Landulf IV, allied against Salerno. Like his father, he attacked Byzantine territories, but was defeated. Capua was forced to become a vassal of the Byzantine Empire, at least officially.