The provision of citizenship by descent had the effect, given the interpretation noted above, of providing citizenship for those in Northern Ireland born after 6 December 1922 so long as their father had been resident anywhere in Ireland on said date. 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". According to Brian Ó Caoindealbháin, the 1935 Act was, therefore, compatible with the state's existing borders, respecting and, in effect, reinforcing them.