The name Clann Mhic Eain means children (or descendants) of the son of John. Eain is a curious form of the more common Gaelic name Eóin that appears in Argyll and parts of northern Ulster circa mid 1400s onward. Eain is also spelled Eáin in modern Irish Gaelic. Gaelic manuscripts prior to the 1600s were written in literary Irish, both in Ireland and Scotland, and in those the name appears as Mac Eóin. By the 1600s a spelling that reflects the Eain form of Eoin appeared. The literary Mac Mhuirich family of Ile spelled the name Mac Eaain and Mac Ea'ain writting in the mid 1600s. Many modern writers render the name as Mac Iain, but the etymology of that form is really not valid. This family uses several anglicised forms of their name, McCain is most common, but McKane, McKain, McKean, and McKeen are also used.
There are several families known as Clann Mhic Eain in the Gaelic world. Some are well known and quite famous such as the families of this name from Glencoe and Ardnamurchan, Scotland. The family I write about however is from County Antrim, Ireland and has roots in mid Argyll, in Kilmichael Glassary. They are obscure in that they have no widely known clan history, but on the other hand are well known in that the family has many famous members, past and present. Their members include the McCains of Mississippi, the McCains of New Brunswick, Ontario, and Nova Scotia, Canada. There is a small army of these McCains in Texas, there from the days of the Republic. Past McCains include admirals, generals, frontiersmen, the early leaders of the Ulster Migration and today the group includes a senator from Arizona, much accomplished barons of business from Canada, musicians and writers of note, etc. all in all they continue to be movers and shakers.
As mentioned their origins are a little obscure, but this is to change in that their history has been researched in the last five years using Y chromosome DNA testing and primary source records in Argyll and Antrim. Enough has been discovered so that a small history book is being written on them, not only to tell their story, but to shed light on the history of their part of Ulster and Argyll. Their history is complex and exist outside the cut and paste standard story of Ulster. Much of Ulster's history has been stereotyped to the point of comical idiocy. The Establish Media trots out well rehearsed Stage Ulstermen to act out these parts. Certain events are used to construct a cartoon like history in which ancient and complex relationships are reduced to one or two events and polices rooted in the 17th Century. The history of real Ulster, of real Aryll, is a wonderful tapestry, rich, beautiful, the players have been on this stage for many thousands of years, the people and place are epic. There is a web site that has bit of the Clann Mhic Eain story and some photos McCains past and present: