s, an oath of fidelity to the British King. Pro-Treaty forces, led by Michael Collins, argued that the Treaty gave "not the ultimate freedom that all nations aspire to and develop, but the freedom to achieve it".
At the start of the war, the Irish Republican Army (IRA) split into two opposing camps: a pro-treaty IRA and an anti-treaty IRA. The pro-Treaty IRA disbanded and joined the new Irish Army. However, through the lack of an effective command structure in the anti-Treaty IRA, and their defensive tactics throughout the war, Michael Collins and his pro-treaty forces were able to build up an army with many tens of thousands of World War I veterans from the 1922 disbanded Irish regiments of the British Army, capable of overwhelming the anti-Treatyists. British supplies of artillery, aircraft, machine-guns and ammunition boosted pro-treaty forces, and the threat of a return of Crown forces to the Free State removed any doubts about the necessity of enforcing the treaty. The lack of public support for the anti-treaty forces (often called the Irregulars) and the determination of the government to overcome the Irregulars contributed significantly to their defeat.
1937 Constitution
On 29 December 1937, the new Constitution of Ireland (Bunreacht na hÉireann) came into force, which replaced the Constitution of the Irish Free State and called the state Ireland, or Éire in Irish. The former Irish Free State government had taken steps to formally abolish the Office of Governor-General some months before the new Constitution came into force. Although the Constitution established the office of President of Ireland, the question over whether Ireland was a republic remained open. Diplomats were accredited to the King, but the President exercised the internal functions of a Head of State. For instance, the President gave assent to new laws with his own authority, without reference to King George VI. George VI was only an "organ", that was provided
