[4] The population in this period is estimated as high as 250,000, and was almost exclusively Christian, except for some Jews living in the main urban centres.

[1][2] Byzantine rule lasted until the late 820s, when a large group of exiles from Muslim Spain landed on the island and began its conquest.

The Byzantines launched repeated expeditions to drive them back, and seem to have appointed a strategos to administer what parts of the island they still controlled.

The successive campaigns were defeated however, and failed to prevent the establishment of the Saracen stronghold of Chandax on the northern coast, which became the capital of the new Emirate of Crete.

[2][7][18] The fall of Crete to the Arabs posed a major headache for Byzantium, as it opened the coasts and islands of the Aegean Sea to piracy.

[7] A major Byzantine campaign in 842/843 under Theoktistos made some headway, and apparently allowed for the re-establishment of the recovered parts of the island as a theme, as evidenced by the presence of a strategos of Crete in the contemporary Taktikon Uspensky.

[2][19][20] Further Byzantine attempts at reconquest in 911 and 949 failed disastrously,[21][22] until in 960–961 the general Nikephoros Phokas, at the head of a huge army, landed on the island and stormed Chandax, restoring Crete to Byzantium.

By the early 12th century, it came, along with southern Greece (the themes of Hellas and the Peloponnese) under the overall control of the megas doux, the commander-in-chief of the Byzantine navy.

[2][7] Aside from the revolt of its governor, Karykes, in 1092/1093, the island remained a relatively peaceful backwater, securely in Byzantine hands until the Fourth Crusade.

[2][7] During the Crusade, Crete appears to have been granted to Boniface I, Marquess of Montferrat as a pronoia by the emperor Alexios IV Angelos.