Ireland was partitioned by the Government of Ireland Act (1920), which divided the island into two self-governing areas. The Anglo-Irish Treaty, signed in 1921, gave Southern Ireland dominion status as the Irish Free State. The treaty was followed by civil war between the Free State government and republicans, led by Eamon de Valera, who rejected partition. The war ended in victory for the government in 1923. A new constitution as a sovereign state (Éire) was adopted in 1937. Éire remained neutral during the Second World War; in 1949 it left the Commonwealth and became fully independent as the Republic of Ireland. The Republic of Ireland joined the EC in 1973