Meaning and Variants of the McDevitt / McDaid Name
The Inishowen family Mac Daibhéid, meaning "son of David" is a name often anglicized MacDevitt or McDaid. Patrick Woulfe in his exhaustive 1923 Irish Names and Surnames says the local pronunciation is "Mac Daeid" and gives other variant spellings McDaveyd, McDeyt, MacDavid, MacDavitt, MacDivitt, Davitt, Devitt, Daid, Dade, etc. (Library Ireland).
A Distinction of Families
Outside the Inishowen Mac Daibhéid, Woulfe listed a family Davitt of County Mayo, but was uncertain as to whether they were descendants of the Inishowen family (Library Ireland). He gives those of a family anglicized McCaveat, MacCavitt, MacKevitt, MacCaet originally of Galway, but now S.E. Ulster and Louth (Library Ireland) and describes a number of other MacDáibhdh families throughout Ireland: two native Irish MacDavid families of Thomond and Wexford, one Scottish familiy (likely members of Clan Davidson), and others that were "a common name among the early Anglo-Norman settlers in Ireland". These he says are oft anglicized McDavid, McDavie, MacDavitt, Davies, Davidson, etc." (Library Ireland).
Ó Dochartaigh Origins of the Inishowen Clann David
The McDevitt family served as emissaries and trusted advisors to the O'Doherty chieftains. Two notable McDevitts were Hugh Boy MacDavitt and Phelim Reagh MacDavitt. Hugh Boy joined the Spanish army and served a number of years, rising to a high officer position. He returned to Ireland in 1594, at the request of Hugh O'Neill, to train the confederate troops and was made chieftain of Clann Daibhéid. Here he served as a trusted advisor to the O'Dogherty chieftain and tutored his young son, Cahir. Having ties to the Spanish, Hugh Boy MacDavitt was involved in arms deals and interpreting between Irish-Spanish negotiations for military aid (which finally came at Kinsale in 1601). Sean Og, the O'Dogherty chieftain, allowed him to live in Burt Castle, which Hugh Boy fortified during his residence. However, in 1602, shortly after being involved in a plot with the O'Dogherty and O'Donnell against the English, Hugh Boy was killed (some believe it was an assassination ordered by the English governor Sir Henry Docwra).
According to the Annals, in 1594 Phelim Reagh MacDevitt was involved in a military incident alongside the O'Donnell in which he killed an English captain. Phelim, along with his brother, Hugh Boy, were the tutors and foster family of the O'Dogherty chieftain's son, young Cahir Rua O'Dogherty. After the death of chieftain Sean Og O'Dogherty, the O'Donnell chieftain placed Sean Og's half-brother as chief. However, in 1601, the MacDevitts, who had reared and trained young Cahir O'Dogherty would not allow their foster-son to be overlooked, despite his young age, and pledged their loyalty to the English governor, Sir Henry Docwra, in exchange for his word that young Cahir would be guaranteed the chieftainship. Both MacDevitts, Phelim and Hugh Boy, along with young Cahir O'Dogherty fought valiantly alongside the English in the last few years of Tyrone's Rebellion, but were not awarded the rebel's lands for their service, as they had been promised. Phelim and Cahir both had run-ins with the politically incompetent new English governor Sir George Paulet. This ultimately led to their starting the O'Dogherty rebellion of 1608 in which many O'Doghertys and MacDevitts fought side-by-side against the English. After 77 days of fighting, Sir Cahir was shot, the English overcome their forces, and captured Phelim after a gallant struggle. After his trial he was hanged, drawn and quartered, and his head placed along side O'Dogherty's on a pike at Dublin.
Y-DNA Evidence for the Ó Dochartaigh Connection?
Y-DNA evidence seems to support the claim of the historic Irish manuscripts that the MacDevitt family of Inishowen is a sept (division of a family) of the Ó Dochartaigh clann. The majority of testers bearing the McDevitt name or variants fall under the R-BY471 Y-DNA subclade. It is within this same subclade that the majority of Ó Dochartaigh testers also fall. So many Ó Dochartaigh and Mac Daibhéid men sharing the same haplogroup (or place in the genetic family tree) indicates they share a common deep paternal ancestry. Below you may see the McDevitt testers among man Doherty/Dougherty testers in Alex Williamson's Big Tree.