The history of Ulster didn't begin with the so called Plantation.
This event has been mythologicised by Nationalism to promote a very dubious race theory and to justify IRA violence.
The so called native Irish are an ethnic mixture from previous migrations from Britain and Europe.
A lot of the so called 'Planters' themselves were Roman Catholics, mostly reiver families from the Anglo/Scottish border, this explains why so many Ulster Catholics have British surnames.
Migration between Ulster and Scotland had been going on for 1000's of years before the Plantation.
The MacDonalds who ruled county Antrim had been importing Scots into their territory centuries before this so called plantation.