Cinnéidigh, King of Thomond

Son of Lorcáin.
WIKIPEDIA PAGE
Succeeded his father in 942 AD as King. Died 951 AD.

had issue (page 298 ALM):

Four of which left descendents:
* Brian
* Mathghamain
* Donn Cuan
* Eichthigheirn

Seven with no descendents:
* Lachtna - Succeeded his father as king in 951. Killed in 953 by the Uí Fhloinn and Uí Chearnaigh. Grianán Lachtna named after him.
* Fionn - Killed at the slaughter at Muighe Dúine.
* Dubh - Killed at the slaughter at Muighe Dúine.
* Marcán - Abbot of Tuamgraney and later Inis Cealtra until his death in 1003.
* Aodh - Killed by Connachtmen.
* Cléirchen - Died of sickness.
* Domhnall - Died of sickness.

Descendents of Cinnéidigh's sons (see ALM p. 235/236)

Brian Borumha

WIKIPEDIA PAGE. Ancestor of the O'Briens. The SNP mutation DC782 (son of ZZ34_1) clearly originated with Brian Boru himself. Many, many O'Briens are under it.

Mathgamain

WIKIPEDIA PAGE. Ancestor of surnames: Ó Beólláin, Ó Spealáin, Ó hAnnracháin, Ó Síodhcháin, Mac Innéirghe, Ó Conghalaigh, Ó Tuama.

Donn Cuan

Had six sons, including two named Cinnéidigh, they were as follows:
* Cinnéidigh - Ancestor of the Muinnter (people of) Chonuing
* Cinnéidigh - Ancestor of the Síol gCinnéidigh (Kennedys). Many Kennedys under DC709 (son of ZZ34_1).
* Riagán - Ancestor of the Muinnter Riagán
* Longargán - Ancestor of the Muinnter Longargán
* Céileachair - Ancestor of the Muinnter Céileachair
* Conghalach - Left no descendents.

According to O'Harts Pedigrees (page 155) the families "Eustace, O'Kennedy, O'Regan, O'Kelleher, O'Beollan (Boland), 0'Casey, Power and Twomey" descend from Donn Cuan. He clearly misattributes O'Beollan and Twomey (Ó Tuama) as they are clearly described as descendents of Mathgamain. He probably confused Mathgamain mac Cinnéidigh as a son of one of the Cinnéidighs who were the sons of Donn Cuan. There is a large Casey surname cluster under FGC5647 (son of ZZ34_1). They are descended from an early 18th century Irish or Ulster Scot immigrant. Assuming O'Hart's source was accurate (much of his sources were lost or destroyed in the four courts fire) then this Casey family could be the one he refers to and descend from Donn Cuan or also from Mathgamain mac Cinnéidigh. However there is also an "Uí Cathasaigh" sept described as descended from Cathasach mac Saithgeal mac Mathgamain mac Toirdhealbhach (see ALM pg. 304) but since this individual was born c. 800AD this is certainly a pre-surname tribal designation.

Eichthigheirn

Ancestor of the Muinnter Eichthigheirn (the Ahearnes)Many Ahearnes (or other variants) under DC38 (the son of ZZ34_1). and Clann Chraith (McGrath). Dalcassian DNA