 The island of Cephalonia was also unsuccessfully besieged in 1085, but was plundered in 1099 by the Pisans and in 1126 by the Venetians.Finally, Corfu and the rest of the theme, except for Lefkada, were captured by the Normans under William II of Sicily in 1185.Although Corfu was recovered by the Byzantines by 1191, the other islands henceforth remained lost to Byzantium, and formed a County palatine of Cephalonia and Zakynthos under William's Greek admiral Margaritus of Brindisi.