Scots Irish were NOT Catholic - they were the ancestors of today's ulster protestants - recall British History - the catholics in Ireland were persecuted by Elizabeth and then during civil war by Cromwellian trops and finally subjugated in 1688 by the forces under the dutch William of Orange - Ulster was planted with a series of walled towns and all the good land was given on lease to a large number (many 10's of thousands) of Scots (originally of Irish descent!) who were strongly protestant - by 1720 these leases were starting to run out and emigration became very attractive to the new colonies in North America where large blocks of land were available at little or no cost - many thousands emigrated usually pushing on as the lands were opened up - they became significant slave owners. Manx tho Protestant were quite different in their attitude to religion - there had been no protestant revolution and the Manx church still had powerful bishops and clergy