How did the Anglo-Irish Treaty create the Irish Free State?

The Anglo-Irish Treaty, signed in 1921, formally ended the Irish War of Independence and established the Irish Free State on December 6, 1922.12

The treaty created the state by granting it the constitutional status of a dominion within the British Commonwealth, modeled after the government system of Canada. Key terms of the agreement included:12

• Governance: The state was established with a governor-general, and members of the Irish parliament were required to take an oath of allegiance to the British king.1
• Partition: The treaty allowed Northern Ireland to opt out of the Irish Free State, which it subsequently did, remaining part of the United Kingdom.12
• Provisional Authority: A provisional government, led by Michael Collins, was set up to implement the treaty's terms.2

The treaty was highly controversial, as many republicans opposed the oath of allegiance and the partition of the island. This ideological divide led to a bitter Irish Civil War, which ultimately resulted in the defeat of anti-treaty forces and the consolidation of the new state.12