However, this automatic entitlement was limited to the first generation, with the citizenship of subsequent generations requiring registration and the surrendering of any other citizenship held at the age of 21.The combination of the principles of birth and descent in the Act respected the state’s territorial boundary, with residents of Northern Ireland treated "in an identical manner to persons of Irish birth or descent who resided in Britain or a foreign country".Nonetheless, London continued to recognise Irish citizens as British subjects until the passing of the Ireland Act 1949, which recognised, as a distinct class of persons, "citizens of the Republic of Ireland".Beginning in 1923, some new economic rights were created for Irish citizens.
(The Article also stated that "the conditions governing the future acquisition and termination of citizenship in the Irish Free State [...] shall be determined by law".) While the Constitution referred to those domiciled "in the area of the jurisdiction of the Irish Free State", this was interpreted as meaning the entire island.
The law grants citizenship to individuals born in Northern Ireland under the same conditions as those born in the Republic of Ireland.
Irish citizenship originates from Article 3 of the Constitution of the Irish Free State which came into force on 6 December 1922, however Irish citizenship applied only domestically until the enactment of the Twenty-sixth Amendment on 5 April 1935 which applied it internationally.
The status of the Irish Free State as a dominion within the British Commonwealth was seen by the British authorities as meaning that a "citizen of the Irish Free State" was merely a member of the wider category of "British subject"; this interpretation could be supported by the wording of Article 3 of the Constitution, which stated that the privileges and obligations of Irish citizenship applied "within the limits of the jurisdiction of the Irish Free State".
However, the Irish authorities repeatedly rejected the idea that its citizens had the additional status of "British subject".