The surname Morrissey and its variations are familiar names in Ireland and in countries populated by the Irish over the generations. In Ireland, it is principally associated with the province of Munster, particularly the counties of Tipperary, Waterford, Limerick and Clare with smaller numbers in neighbouring counties.  The origin of the name, unlike others, is shrouded in some mystery which has exercised the minds of surname scholars and even now a consensus view does not prevail. DNA analysis, so far at least, suggests that there are multiple origins to the name. Therefore, one story cannot describe the development of the many Morrissey families around today. An important goal of the DNA project is to try and tease out, in both a scientific and genealogical way, the origin stories of these families.

The scholar Edward MacLysaght echoes these uncertainties in his popular work “Irish Families”, their Names, Arms and Origins. He describes one native Gaelic sept of O’Muirgheasa in county Sligo, that anglicized their name to Morrissey. This family was a branch of the dynasty called Ui Fiachrach in Connacht. It is doubtful that this Morrissey branch still exists as the families of Ui Fiachrach  generally carry a particular DNA called M222, which, as yet, has not been seen in any Morrissey family to date.

A Norman origin to the surname has been described by MacLysaght and others. In particular, an association with the DeMarisco family that settled in Ireland in the late 12^th century. This family was prominent in the 12^th to 14^th century and its main area of settlement was North Tipperary in an area formerly called Ormond. The DeMariscos became Gaelicized quite early on and adopted an Irish version of their name, MacMuirgheasa. This is believed to have been later anglicized to Morris and Morrissey with the Mac being lost and not subsequently restored. To date, there is no real evidence of Norman or Old English Y-DNA in the Morrissey men tested so far. However, there is a large group of Morrisseys tested that carry the DNA marker L161.  Analysing the geographical origins and associated surnames of this group shows a connection to the area of North Tipperary associated with the DeMarisco family. The most common recent ancestor of all members of this group appears to be quite a number of generations back, likely to the 13^th to 14^th century. Therefore, some connection to the DeMarisco family is possible, but not likely a genetic connection to the original settlers.   

MacLysaght and another surname scholar Fr. Patrick Woulfe both comment on the occurrence of forms of the name with an associated O’ such as O’Morrissey etc. This would usually denote a native Gaelic family. A number of Morrisseys tested do possess Y-DNA that is considered Gaelic, which provides evidence for the existence of Morrisseys of Gaelic origin. The ancient Irish forename Muirgeas may provide a basis for the origin of these particular families.

Several resources from the 16^th and 17^thcentury provide insight into the variety of forms of the name during a period of transition. Many surnames in Ireland became progressively anglicized during this period. Changes in the structure of names is seen as well as the omission of O’ and Mc/Mac in many situations. The Fiants of the Tudor monarchs, The Hearth Money rolls and the “census” of 1659 all demonstrate a variety of forms of Morrissey. Clear phonetic examples of Morrissey occur as well as the widespread use of the MacMorris and Morris form in areas that the familiar Morrissey form now dominates. For example, in County Limerick, McMorris is the most widespread form in 1659 and is quite numerous in some of the baronies where Morrissey is now the usual form. McMorris as a name is now very rare in Limerick.

As can be seen, conventional research on its own does not provide sufficient information to explore the origin and development of the surname.  The addition of DNA provides another avenue of research.  We would encourage eligible testers to join the project and in time we can hopefully provide answers to some of the questions posed above.