Saint Pachomius
Saint Kevin of Ireland.
Irish monks did and do live in Ireland in a Monastery.
the vikings first raided the monastery of lindersfarne.
In ScotlandVampires were first found in Ireland
Monte Casisno was his first monastery.
Ireland was first settled around 10,000 BC. It is thought that the landbridge with Britain has disappeared by that stage so the first settlers would have arrived in Ireland by sea.
Benedict
Saint Benedict started his Monastery in Monte Cassino.
Rome
He says he was found on the doorstep of a monastery during the desert scene.
I'm not sure I can verify that it is the "first ever" monastery, but I do know that it is widely accepted that St. Anthony is the father of Christian monasticism. His followers founded the Monastery of St. Anthony in Egypt in 356 CE.
The McBrien surname is first found in the records of Thomond, Ireland.