He was duly elected by the Norman nobles of Aversa and invested with the countship by his suzerain, Guaimar IV of Salerno.
Asclettin did not immediately come into possession of the duchy of Gaeta, which Ranulf had ruled as a vassal of Guaimar.
Instead, the Gaetans chose Atenulf, Count of Aquino, as duke.
Guaimar attacked and defeated him on behalf of Asclettin, but in return for his assistance against Pandulf the Wolf, then assaulting Monte Cassino, he freed him and confirmed in Gaeta.
His younger brother Richard later succeeded to Aversa and brought the family the principality of Capua as well.