 Successive campaigns by the emperors of the Heraclian dynasty in Greece also led to the recovery of control of Central Greece from Slavic invaders, and to the establishment of the theme of Hellas there between 687 and 695.Sicily too was formed as a theme by the end of the 7th century, but the imperial possessions in mainland Italy remained under the exarch of Ravenna or the local "doukes", as did Byzantine Africa until the fall of Carthage in 698.At the same time, Crete and the imperial exclave of Cherson in the Crimea formed independent "archontiai".