Cyprus was divided when, on 20 July 1974, Turkey invaded and occupied a third of the island in response to an Athens-engineered coup aimed at annexing Cyprus to Greece. Since then, Turkey has refused to acknowledge the Republic of Cyprus (an EU member since 2004) as the sole authority on the island, and recognizes the self-declared Turkish Republic of Northern Cyprus since its establishment in 1983. The Turkish invasion in 1974 and the resulting movement of refugees along both sides of the Green Line, and the establishment of the self-declared Turkish Republic of Northern Cyprus in 1983, form the core issues which surround the ongoing Cyprus dispute.