[1][2] The Cotters are noted as one of the very few Irish families of verifiable Norse descent to survive the Norman invasion of Ireland,[3] although it is currently unknown if this is genetically paternal or only maternal.

This question mattered considerably less to the Norse of the period than to the Gaelic Irish, whose entire rigid class structure was and remains based on agnatic descent.

There is a record of a possible member of the dynasty, one Óttar Svarti ("Ottar the Black" - in Irish it would have been rendered 'Oitir Dubh'), an Icelander (connections between Iceland and the Norse settlements in Scotland and Ireland were relatively close), addressing Cnut, King of England and Denmark, in a praise-poem: "Let us greet the king of the Danes, the Irish, the English and the Islanders; his praise travels through all the lands under heaven."

[6] It states that after the combined forces of him and Ragnall ua Ímair raided a number of places in Munster, they then split into three parties, one of which settled in Cork.

[8] Ottir appears to have joined Ragnall in battle, or possibly led an expedition of his own, against Constantine II of Scotland in or around the year 918, and perished then,[9] for which see his article.

Lacking sources, it cannot be demonstrated that the Cotters of Cork or Mac Ottir of Dublin descend from this Jarl Ottar, but he did live in the right period for his name to be adopted as a surname.

The chronology and nature of Jarl Óttar's rule in the Isle of Man is unclear, though his death in battle on the island in 1098 is consistently referred to.

The chronicle then states that the after effects of this Manx civil war was the reason that Magnus Barefoot was able to take the island with ease later the same year.

[12] If the latter version is accurate then Óttar would appear to have been a sovereign prince within the island before the arrival of Magnus Barefoot, rather than a royal vassal.

All versions agree that in 1098 a battle was fought between the forces of Óttar, with many men from the north of the island adhering to his cause, and those of MacManus or Macmaras at Santwat (Santroust or Sandwath).

[17] Thorfin was instrumental in the replacement of Godred II Olafsson as the major power in the Hebrides by Dubgall the son of Somerled.

[20][21] The historian Gareth Williams has postulated a kinship link between the mother of Dubgall, Ragnhildis Ólafsdóttir, and the Óttar family which may also have affected Thorfin's political inclinations.

The expedition was defeated in a naval battle at Dungarvan or Youghal, the Ostmen attacked using axes and slingshot, the Normans replied with bows and crossbows.

Possible evidence that the Cotter family maintained "foreign" interests may be the presence in the 15th century of one Murdo MacCotter in Orkney, fighting under the head of Clan MacLeod of Harris.

From the late 15th century, if not earlier, two main branches of the Cotter family in County Cork are evident, one based at Coppingerstown Castle, the other at Inismore (Great Island, Oileán Mór an Barraigh, on which the port of Cobh, formerly Queenstown, stands).

[29] A number of placenames in East Cork, including Ballymacotters and Scartmacotters, attest to the presence of the Cotter family from an early date.

"[30][31] The ancestry of this branch is more fully documented, the earliest recorded member is a William Cottyr who flourished during the reign of King Edward IV (1461–1483).

Large areas of Inismore seem to have been held by the Cotter family from 1572 at the latest, when Edmond Buidhe and William Óg MacCoter are mentioned in a deed.

In 1691 Cotter was made Brigadier General in command of all the Jacobite forces in counties Cork, Kerry, Limerick and Tipperary.

He was rewarded for his moderation when, following the surrender of the Jacobite forces under the Treaty of Limerick, the support of his Protestant neighbours allowed him to retain his property and lands in full.

Domhnall Ó Colmáin included much biographical material concerning Sir James in his tract Párliament na mBan.

James Fitz Edmond Cotter married twice (the first marriage without issue), his second wife being Ellen Plunkett daughter of Matthew, 7th Lord Louth.

His eldest son, James, inherited his wealth and patronage of the Catholic population of Cork, but not his astute political instincts and ended his life on the gallows.

[41] James Cotter the Younger (Séamus Óg Mac Coitir) was the victim of a celebrated case of judicial murder and was executed in Cork City in 1720.

Ultimately, the descendants of Sir James Fitz Edmond Cotter retained their wealth and political prominence, but at the cost of losing the faith and culture their ancestors long upheld.