The Scottish prefix now generally written as Mac has over history also been written as M' and Mc. It is variously prounced as MK or M plus a glottal stop, depending on the next sound. The prefix means "son of..." and was originally followed by the given name of a man's father. There is a similar prefix nic for "daughter of...".

These combinations also occur in Ireland. The Scots originally came from Ireland in the 4th and 5th centuries CE, displacing earlier peoples like the Picts. A similar particle indicating descendancy - ap - occurs in Welsh.

There is no meaningful difference between the spellings. That said, people seem to attach meaning where none should be found. There is a preference for Mac in Scotland and Mc in Ireland, but both forms occur in both cases, and often within families.

Since the English subjugation of the Welsh, Scots, Irish and other Celtic neighbors from 1000 CE to the 20th Century, the fortunes of people with Celtic names have risen and fallen with regional politics. Added to the mix were religious differences among Catholics v. Protestants Catholics vs. Catholics, Protestants v. Protestants and, of course all other possible combinations. (Scorecards are available at the door.) At times it has been fashionable, or unfashionable, to be perceived as Scottish or Irish or Welsh or English, both in Britain and Ireland and in North America.

In my own family and others related by marriage, the Mcs and Macs are a spelling challenge. Was my great-great-grandmother Catherine MacDonald or Catharine McDonald or Catherine McDonald? (First names get misspelled, too.) My great-grandfather Thomas McKee was born in Scotland the son of Thomas McKee, who was born in Ireland, but the younger Thomas took his mother's name Goodwin in America to avoid anti-Irish prejudice and to ally himself with more prosperous relatives. In fact they were not culturally Irish but "Plantation Scots" who presumably went to Northern Ireland in the 17th Century and then returned to Western Scotland by the time of the great Irish famine of the 1840s. Letters to my great-grandparents in the late 19th and early 20th centuries from close relatives named McKee, McKay, and MacKay, who reference one another as brothers and cousins.

So in fact we never really know who comes from whom. It's all very interesting, but ultimately it is the future we must address, not the past.

When I was a kid briefly I took to spelling my name Clarke. It lasted a few months until I decided it was a waste of ink and reverted to Clark. Probably as good a reason as any. But had I persisted it might have confused the heck out of folks in the 22nd Century.

Alex Rees Clark: Finally, my middle name derives from the Welsh Rhys, with the Rh indicating a trilled R. I got (most of) the middle names of my two grandfathers, Perry Alexander Clark and Ephraim Rees Davis. But please call me Rees. My mother started calling me by my middle name when I was two or three. (Could have been worse, I might have spent my playground years as "Eph.") When I speak in Spanish to people from Latin America, I adopt the Spanish form of Alex/Alexander, Alejandro, which is immediately recognized while Rees occasions a strange stare. Who are we, really, if not the person we seem to those around us.