The Theme of Cephallenia is frequently mentioned in military operations in the 9th–11th centuries. In 809, the "strategos" Paul defeated a Venetian fleet off Dalmatia. In 880, the admiral Nasar heavily defeated an Arab pirate fleet that was plundering the theme's islands, and troops from Cephallenia subsequently participated in the Byzantine offensive in Italy. Mardaites from Cephallenia are then recorded in the failed expedition of 949 against the Emirate of Crete. The last mention of a "strategos" of Cephallenia comes in 1011, when Kontoleon Tornikios was sent to Italy to quell a Lombard revolt. Following the collapse of Byzantine control in southern Italy in the mid-11th century, the theme's importance declined, and it was headed by civilian governors, styled "krites" ("judges").