Let's say that, some time during the decline of English authority in Ireland during the 1300s, there arises among the native clans a charismatic warlord that unifies all the clans into a kingdom, and drives the English out completely. Let's say also that he is good enough at statebuilding so that the kingdom doesn't fall apart after his death. What would a unified Kingdom of Ireland look like, and what would it do to European politics in general?