Venetian rule in the Ionian Islands to south, including their Greek and Italian names in parentheses: Cythera and Lefkada were additionally called ' or ' and " respectively by the Ottomans. During the Roman Empire, the Ionian Islands were variously part of the provinces of Achaea and Epirus vetus. These would form, with the exception of Cythera, the Byzantine theme of Cephallenia in the late 8th century. From the late 11th century, the Ionian Islands became a battleground in the Byzantine–Norman Wars. The island of Corfu was held by the Normans in 1081–1085 and 1147–1149, while the Venetians unsuccessfully besieged it in 1122–1123. The island of
United States of the Ionian Islands and Russia signed the Treaty of London, pledging the transfer of sovereignty to Greece upon ratification; this was meant to bolster the reign of the newly installed King George I of Greece. Thus, on 28 May, by proclamation of the Lord High Commissioner, the Ionian Islands were united with Greece. According to the second constitution of the republic (1803), Greek was the primary official language, in contrast to the situation in the Septinsular Republic. Italian was still in use, though, mainly for official purposes since the Venetian Republic. The only island in which Italian (Venetian) had a wider spread was