This notable surname is an Anglicized form of the Old Gaelic "O'Dochartaigh", descendant of Dochartach, a personal byname meaning "Hurtful, Injurious". Traditionally, Irish family names are taken from the heads of tribes, revered elders, or some illustrious warrior, and are usually prefixed by "Mac" denoting "son of", and "O", grandson, male descendant of. Originating in the barony of Raphoe, County Donegal, this large and powerful sept were of the same stock as the illustrious O'Donnells of Tirconnell (County Donegal), one of the most famous septs in rish history. By the 14th Century the O'Dochartaigh chiefs had extended their territory till they became Lords of Inishowen, and their headquarters was on the Inishowen Peninsula. In 1208, one David O'Doherty, a chief of Cinel Conaill, was killed in battle, and from him descend the Mac Daibhid or MacDevitts of Inishowen. The power of the O'Dohertys was greatly reduced following the ill-timed rebellion of 1608 led by Sir Cahir O'Doherty, and several of the sept fled to Scotland, the Isle of Man, and England, where the name was variously Anglicized as Do(u)gherty, Daughterty, Docherty and Docharty. The family Coat of Arms is a silver shield with a red stag springing, on a green chief three mullets of the first. On April 24th 1655, Ellin, daughter of William Doherty, was christened at Derry Cathedral, Templemore, Londonderry. The first recorded spelling of the family name is shown to be that of Donnall O'Dochartaigh, which was dated 1119, in the "Manx Names", by A. W. Moore, during the reign of Turlough Mor O'Conor, High King of Ireland, 1119 - 1156. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.