After the unilateral declaration of independence by the Irish Parliament in 1919, the IRA continued the war against British occupation in what was called the Irish War of Independence. This ended in 1921 with the signing of the Anglo-Irish Treaty, which divided the island into the Republic of Ireland and Northern Ireland. The signing of the treaty led to a split in the IRA between those who were against the treaty and those who were for it. This led to a very bitter civil war, which saw former friends and even family members on different sides. The IRA lost the civil war but the group did not go away and they continued to fight Great Britain.