Donkey's years

• for donkey's years: (phrase) for a long time

• donkey → the Ass or Donkey who always accompanies the Four Old Men here represents the fifth province of Ireland (i.e. the no longer recognised royal province which included Tara within its boundary)

Commentary

Thus, too, for donkey's years.

This phrase identifies the fifth of Ireland's "five fifths" or provinces, the royal province (known later as Meath).

Ireland has only four provinces today – Ulster, Munster, Leinster and Connacht – but in the early Christian centuries there were five provinces or fifths, the Middle Irish word coiced (Modern Irish: cúigiú) meaning both fifth and province. The fifth province was the royal province that included Tara, the seat of the High Kings of Ireland. It corresponds roughly to the modern counties of Meath, Westmeath and Longford, with parts of Dublin, Offaly and Louth, all of which are now considered to be part of Leinster.