In fact, as long ago as 1963, the Ankara Agreement established the possibility that Turkey might join the European Union, with the association agreement to evolve through an initial stage, a transitional stage and a final stage.
Allerede i 1963 blev der i øvrigt i Ankara-aftalen åbnet for den mulighed, at Tyrkiet kunne blive optaget i EU i takt med udviklingen i associeringsaftalen gennem dens indlednings-, overgangs- og slutfase.