Recorded in many and varied spellings including: O'Halligan, Halligan, O'Hollegan, Holligan, Holgan, and Olligan, this very interesting name is medieval and Irish. It derives from the original pre 10th century Gaelic O' hAileagain', meaning 'a descendant of Aileagan', the later being a personal name derived from 'aille', meaning beauty! The clan O'Halligan is an Oriel sept from counties Louth and Armagh, and it is claimed have been recorded there as early as the year 1042. In the ancient rolls and charters the surname is first recorded O' hAllagain, and later in the 17th century in Connacht as O' Hallagan and O' Hollegan as it is today. In Dublin the spelling seems to have been Holgan from early times, with Patricke Holgan, the son of Walter Holgan, being christened at St Michans church, on August 1st 1641. Other sample recordings in Ireland include James Hollegan, who left Ireland on the ship "Arabian of Liverpool" bound for New York on June 19th 1846, at the very begining of the infamous Potato Famine, the christening of Margarett Halligan, the daughter of Turlagh Halligan, on February 14th 1655 at Derry Cathedral, Templemore, and the birth of James Hallegan on May 24th 1864 at Monasterboice, County Louth. The first recorded spelling of the family name is possibly that of William O' Halegan, which was dated 1597, in County Kildare. Throughout the centuries, surnames in every country have continued to "develop", often leading to astonishing variants of the original spelling.