The Irish Free State removed the oath of allegiance to the Crown in 1933 , when Éamon de Valera’s government passed the Constitution (Removal of Oath) Act.

What that meant

  • The oath had been a requirement under the 1922 constitutional settlement.
  • Its abolition was one of the key steps in dismantling the Free State’s remaining links to the British Crown.
  • Other major changes followed later, including the removal of the Governor-General and further constitutional revisions in 1936–1937.

Small timeline

  1. 1922 : Irish Free State established with the oath built into the constitutional order.
  1. 1933 : Oath abolished.
  1. 1936–1937 : Further dismantling of Crown-related links and adoption of a new constitution.

The short answer is: 1933.