Malta was ruled by the Byzantine Empire, from the time of the Byzantine conquest of Sicily in 535-6 to 869-870, when the islands were occupied by Arabs. Evidence for the three centuries of Byzantine rule in Malta is very limited, and at times ambiguous. Historians theorise that Byzantine Malta was exposed to the same phenomena affecting the Central Mediterranean, namely a considerable influx of Greek settlers and Hellenic culture, administrative changes brought about by the reorganisation of Sicily along the lines of a Byzantine theme, and significant naval activity in the Mediterranean following the rise of Islam.