“Known as the Black Irish....black guys named McMillan, McDonald...”
If my memory serves, the Black Irish are the result when nice Catholic Irish girls meet nice Spanish Catholic shipwrecked guys after the Spanish Armada in Queen Elizabeth’s day is totally destroyed by a big storm.
The Mc Blacks probably took the names of their masters after the Civil War. Perhaps they were less badly treated by what may have been Irish and Scotch smallholders who had personal contact with slaves, rather than large landowners who may have had more wealthy English roots. I know that there are a lot of black Williams’s which would be Welsh, who had no great love for the English. In fact the name Williams means “Williams man”, dating from when many Welsh allied themselves with William the Conquerer against the English.
You have to give the Spanish credit for spreading their seed far and wide...even in places that they never conquered or held on to for very long. Years back when I first moved to Louisiana, I was kind of surprised at the number of Spanish surnames that have held on here from even before the arrival of the French Cajuns. Some of the family names include Ortego, Romero, Villareal, etc. although all are pronounced in very flat English, and not with the Spanish pronunciation and inflection you'd expect in more recent immigrant communities. Likewise, if you meet a native born Louisianian with the surname, "Rivers" there's a good chance that has been anglicized from "Rivera."