This interesting Irish surname is of ancient origins. It derives from the pre medieval Gaelic name O' Maolchathail translating as 'The male descendant of the follower of St Cathal', a 7th century saint. It is claimed that the clan originated from County Leix, where the name in former times was prefixed with the O.' Recorded as Mulhall, Mullhall, Mulhill and Mulcahill, it appears in County Tipperary as Halley. These Halleys were originally Mulhalls who changed their name in the 18th century, probably for political reasons. Irish surnames traditionally descend from the personal or nickname for the original chief of the clan, or as in the case with this name, a famous early saint. In Ireland the use of surnames from occupations or locational are rare, and the use of the O' prefix which had largely died out, is now making a comeback in some places as is the use of the original Gaelic spelling. Early examples of the surname recordings taken from surviving church registers of Ireland include Christiana Mulhall who married Edward Spring at the church of St Peter and St Kevin, Dublin, on April 2nd 1716, and Fanny Mulhall who married Thomas Brian at Carlow, County Carlow, on June 5th 1780.