If it wasn't for the English there might not be any Irish. An Irish king invited the English to help out against the Vikings who were wiping out the Celts tribe by tribe. There was no Ireland just competing tribes
This is so many kinds of wrong I don't know where to start 
Viking activity and incursions was intense in only parts of Ireland. There was no huge Danelaw like in Britain. Some parts of Ireland (esp the west) saw nary a Viking at all.
Vikings in Ireland were mostly trade-based, not raiders. The raiding mostly stopped when it became obvious there was more money in trade and the Viking settled down establishing seaport cities. There was never any chance of Vikings wiping out the Irish. (They were too busy marrying in, especially around Dublin).
Gaels, not Celts.
Ireland was under a single High
King (albeit in a kind of first-among-equals federal sense, since Irish kings didn't do absolute political rule) when the Romans were in Britain, possibly longer. There has been a cultural Ireland longer than there has been a cultural Britain or England.
Tribes? Do you mean clans or kingdoms? They weren't hunter-gatherers ffs.
An Irish King invited the English to help out against the Vikings.. Really? Are you confusing Diarmuid MacMurrough's invitation of the Normans to Ireland (to reclaim his kingdom when it was seized by the high king) with an anti-Viking campaign? There were no raiding Viking then and hadn't been for hundreds of years.
Sheesh...