To date all Fitzpatricks who trace to Iveagh and other parts of County Down that have taken DNA tests have been found to be haplotype Z255>Z16434>BY2851>BY2849. The haplogroup Z255 is known as the 'Irish Sea' or Leinster Modal haplotype, hence it comes as no surprise that Iveagh Fitzpatricks have many cousins who trace to Leinster. Dominant surnames amongst those Leinster cousins in the other main sub-groups of Z255, i.e., Z16429 and Z16437, are Byrne, Beatty, Gleason and Carroll. Z16434, who is the common ancestor of Iveagh Fitzpatricks, arose ca. 620 AD in Leinster, but these were turbulent and changing times as the ancestors of Iveagh Fitzpatricks were about to witness first hand.
Be it Viking invaders or overseas opportunities it appears some Z16434 men, probably in small family groups, left Ireland's shores. One such group are the Z16434>BY17850 Irelands; their exodus to Scotland was prior to the use of patronyms, hence it makes perfect sense they may have taken a surname that forever linked them with their former homeland. Another group are the Z16434>BY2851>BY23533 men with Welsh surnames; these are the closest pre-patronym cousins of Z16434 Fitzpatricks and likely descend from settlers on the Llŷn Peninsula.
The figure illustrates the exodus of BY2849 probably as a flow-on result of the Norman invasions of Leinster. Of note is the old formation of BY2849 (ca. 1100 AD) and the early formation of distinct sub-branches dating to ca. 1400-1600 AD and 1200-1400 AD, respectively. SNP markers under BY2849 are now so well defined they can readily distinguish Newry Fitzpatricks (BY17992), from Iveagh Fitzpatricks (BY2893), from Co. Louth Fitzpatricks (BY52612). Iveagh Fitzpatricks can be further defined by BY34974, a recent (ca. 1750 AD) branch that formed in Kilcoo Parish, which distinguises them from Fitzpatricks who trace to Kilkeel Parish in recent times. You might enjoy viewing the TMRCA Matrix and haplotree.© OpenStreetMap contributors
The surname Fitzpatrick comes from Giolla Phádraig, which the Irish Annals record as first being used in a nominative form in 982 AD and is widely associated with the Kings of Osraige.
On submission to Henry VIII in 1537, Brían Óg Mac Giolla Phádraig became Barnaby Fitz-Patrick, the first Baron of Upper Ossory. However, other Mac Giolla Phádraig lines appear to have retained their Gaelic surnames, or transliterated versions such as MacGilpatrick or MacKilpatrick, for much longer.
The use of MacGilpatrick in Iveagh is found in the Patent Roll of James 1 in 1611; for example, amongst the pardons of several Magennis chiefs of Iveagh is a Turlaghe McGilpatricke. Although it is not fully certain if these uses of MacGilpatrick were patronymic it is not implausible, and by the time of the Pender’s Census (1654-1659), McIlepatricke is listed as one of the ‘Principall Irish names’ in the Barony of Upper Iveagh.
What forces led Mac Giolla Phádraigs from Leinster to settle in Newry and Iveagh? Some clues can be found by understanding who these Mac Gilpatricks were associated with.
That MacGilpatricks settled in Newry and Iveagh, perhaps as early as ca. 1200-1400 AD, suggests an association with the local clans, chief of whom were Magennis and MacCartan. There are hints of possible connections, such as the soon to be mentioned Neese McIllepatrick - the name Neese shares it's derivation with Magennis. And there are several appearances of Giolla Phádraig in the genealogies of the McCartan Clan
It is well established that during the Nine-Years' War (1593-1603) Hugh O'Neill sought the support of Florence Fitzpatrick, the third Baron of Ossory. Florence refused, but the Baron's kin, including his son Teige, pledged their loyalty to O'Neill. Subsequently we find record of a Neese (Nice) McGilaptrick pardoned alongside several chiefs of the Clanaboy O'Neill; those pardons most likely relate to events during the Nine-Years' War. It is somewhat ironic, though not uncommon in that day, that it appears likely there were MacGilpatricks who fought alongside O'Neill at the Battle of the Yellow Ford, while in the English army the body of Irish auxiliaries were led by the Baron of Ossory, who carried the standard of Elizabeth I.
As well as the recorded appearance of Mac Giolla Phadráigs in Iveagh, O’Hart refers to Mac Giolla Phadráigs from Ossory who migrated to Bréifne. Where they went exactly and who their ancestors are today is a mystery. The DNA project has established there are Fitzpatricks who trace to Cavan and neighbouring counties who are either haplotpe L513 or FGC11134. Since the latter group are particularly large and is marked by a block of Fitzpatrick specific SNPs, including BY9002, that are old (later than ca. 450 AD) they are likely to have been associated with Mac Giolla Phadráigs from Ossory. The DNA project is endeavouring to uncover more about this group. In any case it's likely there will be many others, genetically distinct, who can also claim to be Mac Giolla Phadráig Ulaid - MacGilpatrick of Ulster.
A Neese McIlepatrick, who is possibly the same individual mentioned in the Patent Roll, is also referenced in the earliest land record found to date for any Fitzpatrick in County Down. The 1663 Subsidy Roll for the Lordship of Newry and Mourne names Neese McIlepatrick of Ballygoan (Ballygowan). Ballygowan, which means ‘Town of the Smith’, is a townland in the Barony of Mourne overlooking Carlingford Lough, just a few kilometers from Greencastle.
Reference to Neese also occurs in the Rental Roll of the Bagenal Estate, July 1688. There we read:
‘Ballygoan formerly lett to Neece McIlepatrick the smith and now lett to his son Owen and the rest’.
Iveagh Fitzpatricks share a strong genetic link with Fitzpatricks who trace to Monasterevin (Monastery of St Evin) in County Kildare. This link is from ca. 1500 AD and provides evidence of a prior-homeland in Leinster for Iveagh Fitzpatricks. Just a few miles south of Monasterevin is a townland called Kilpatrick, which is generally taken to mean 'Church of Patrick'.
However, just like the Fitzpatrick surname, this townland underwent a name change. It was previously called Grange Mac Gillepatrick (or M'gilpatrick) and was a farm, or similar, associated with the Monastery. It is considered the townland was probably in the possession of Mac Giolla Phádraigs prior to the Dissolution of the Monasteries, and certainly before 1567, when it was recorded in the Fiants of Elizabeth I as being surrendered by Edward Waterhouse (later to be re-granted), who was the Chancellor of the Exchequer of Ireland from 1586 to 1589.
A fine piece of genetic detective work from the Fitzpatrick DNA study is recent the discovery of the connection between Fitzpatricks of Iveagh, Newry and Mourne, and those from Rathdrummin, County Louth. The two groups share a common ancestor from ca. 1000-1200 AD, and although the presence of Fitzpatricks in Rathdrummin was well established by the mid 1700s nothing is known of their line prior to this. However, they believed their Leinster roots were from old times. The 'Louth Letters', which contain accounts taken from the oldest inhabitants the Parish, state 'The Fitzpatricks or Mac Giolla Patricks were chiefs of Ossory or Kilkenny before the Normans came'. Several families of Rathdrummin Fitzpatricks left Ireland in the 1830s; they were the forebears of many Louth Fitzpatricks living in the USA today.