Argostoli, Kefalonia, Greece - British Monument commemorating the Britsh Occupation of the Grecian Islands in 1818. The United States of the Ionian Islands was a state and amical protectorate of the United Kingdom between 1815 and 1864. It was the successor state of the Septinsular Republic (created by occupying Russo-Turkish forces), who had driven out the French. It covered the territory of the Ionian Islands, located in modern Greece, to whom it was ceded as a gift of the United Kingdom to the newly enthroned King George I, at the end of the protectorate.