Page "Constitution of the Irish Free State" Paragraph 15

Both the British and Irish Acts provided that the Constitution would be brought into force by a royal proclamation, which was accordingly issued on 6 December.

The Constitution thus came into force on 6 December, the latest possible date allowed for by the Constitution itself.

On this date the members of the Dáil took the Oath of Allegiance, and nominated the members of the Executive Council ( cabinet ).