This most interesting surname, of Gaelic origin, is possibly a variant of either "Domegan", a rare east Leinster name or "Donegan, Dunnigan", the name of several unrelated septs. The former is the Anglicized version of the Gaelic name "O'Domagain", composed of the Gaelic prefix "O", male descendant of, and a personal name which is composed of the Gaelic "doma", poor. Alternatively, the name may be a rare variant of "Donegan", the Anglicized form of the Gaelic "O'Donnagain", derived from the Gaelic "donn", brown, and was the name of at least four distinct septs in medieval Ireland, two in Co. Cork, one in north Tipperary and in Co. Monaghan. In the 17th Century, Donegan, Dunnigan was widespread in the Counties of Roscommon and Westmeath. John Dongan was Bishop of Down, 1394 - 1412, while Thomas Dongan (1595 - 1663), who after being reduced to dire poverty after the 1641 Rising, became a Baron of the Exchequer at the Restoration. Richard Dummigan married Jane McGladdery at Dromore, Co. Down on December 22nd 1805, and James, son of Thomas and Margaret Dummigan, was christened on February 14th 1829 at Magheralin, Co. Down. The first recorded spelling of the family name is shown to be that of Donnchady O'Donnagain, King of Fernmhagh (Farney, Co. Monaghan), which was dated 1026, in the "Annals of Loch Ce", during the reign of Irish High Kings in opposition, disputed succession. 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.