Primogeniture was not the basis for succession
Dynasties and Monarchies change from one ruler to another most of the time by the rule of the sword. One just has to look at the Chinese, Roman and English or all other dynasties around the world. I do not believe Ireland was immune to this effect happening among their clans. Irish genealogist and Episcopal scribes adjusted the pedigree of the ruling clan or whom ever was in power at the time.
The Irish clans or septs resolved problems within their own clan . Family groups called Derbh-Fine. Centering around one leading family from who the chiefs was always elected. Whether a Chief or King was hereditary only to the extent that the king or Chief was always chosen by the people , from within the clan.
The Righ Damna
'Kings Material’, that was Royal uncles, brothers, sons, nephews, grandsons and grandnephews the people chose whatever male member was the bravest, wisest and best fit to rule and lead the clan.
In ancient Ireland there were many marriages among the Ui Neill and Norse and other various races that occupied Ireland. Many chiefs died or were slain in battle and the Righ Damna could have been a descendant of any male descendant of a male or female of the clan.
Marriages among the Gael clans and the Norse occurred more than often especially in the Hebrides Isles. In the middle of the 9th century Muirgel, the daughter of Maelsechlainn I of the Ui Neill married the Norse Larnkne. Amhloabh, son of the king of Norway, married the daughter of Aed MacNeill. There are old stories of Irish Chieftains who were levying tribute on the Shetlands, the Orkneys and the Faroes. Sigtrygg's elder brother and predecessor as king of Dublin, Gluniarainn, his half brother and brother in law was Maelsechnaill mac Domnall. 1098 A.D. Norwegian King ,Magnus Barelegs . He had conquered the Hebrides and the Isle of Man. He married Muirchertach's daughter when he was killed in Ulster in the year 1103 he sent her back to her father. He left a son King Harold Gille, who was born in Ireland or the Hebrides Isles.
I will always use this has a perfect example : Julius Caesar adopted Octavian , son of Attia, Octavian later became known Agustus and adopted the surname Caesar to comply with the will of his mothers uncle Julius Caesar.
The O'Neills of Ulster take their surname from Niall Glundubh Mac Aedo 10th century High King of Ireland and King of the Cenel Eogain . Not from Niall of the Nine Hostages that should be made clear. There is genealogical evidence that there was a Njall Glundubh born in Norway circa . 850 A.D.
The Ui Neill is the clan of Niall and his descendants.
The Pedigree of Niall Mac Eochu latter known has Niall of the 9 Hostages. their should be great sceptisim considering to whom Niall of the 9 hostages was related and how his history was created. his rise to power is based on myths and legends.
1. No archealogical evidence has been found of Niall of the Nine Hostages Kingship in Ireland?
2. No ancient bones of Niall has been found or discovered to perform a y-DNA test?
The son of a slave girl , Cairenn , daughter of the Saxon King of Britain or the daughter of the King of the Britons. Depends on what the Irish genealogist wanted you to believe or what book you read.
1. IGNE RI ALL SAXAN
2. INGHEAN RIOGH BRETON
The Legend of Niall of the 9 Hostages
Niall was the son of Eochaid Muig-Medon ( Lord of Slaves) King in the middle of the fourth century. Niall’s mother was Cairenn Cashdubh ( Black Head, Curly Black Hair) the daughter of Sachell Balb ( Sachell the Stammer) the Saxon king of England. Some say he was the Celtic king of England. Niall had four brothers Brian, Fiachra, Ailill and Fergus. All king Eochaid Muig-Medon first wife Mong-Fionn. Mong-Fionn it is said to have been a ambitious woman and wanted her son Brian to succeed his father has king. (Mong-Fionn was the daughter of Fiodach, and sister of Crimthann, King of Munster or King of the Laigin). Niall was said to have been the favorite of King Eochaid Muig-Medon. Mong -Fionn was set to outcast Niall and his mother Cairenn. One story has Niall being abandoned as a baby, naked on a hill. Rescued by the Poet Torna Eices. she raised him and educated Niall to he reached manhood. During this time Nialls mother Caireen was doing menial tasks in the courts.
One Legend out of many.
All the five brothers Brian, Fergus, Ailill, Fiachra and Niall were at Sithchenn the Smiths forge when it caught fire, they were commanded to save what they could. King Eochaid Mug-Medon watching his sons observed Niall good judgment. Has he saved the Smiths Anvil, the bellows, the sledges, and saved Sithchenn the smith from ruin. From this event Niall was said to become the King.
One day all the five brothers were hunting, and all of them sorely thirsted, they discovered a well , in the woods, guarded by a old hag , who granted a drink to the person who had the courage to kiss her. None of the brothers would . Niall went forward and kissed her the old hag turned into a beautiful maiden named Flaithus " Royalty".
Eochaid Muig-Medon dies at Tara and Mong-Fionn has her brother Crimthann take the crown and become king until her son Brian was of the right age to lead. Instead Crimthann becomes a real king with successful expeditions against the Britons, Gauls and Picts. He reigns for twenty years until Mong-Fionn poisons her brother and to avoid suspicion drinks from the same cup and dies. Niall begins his reign in 379 A.D.? He becomes known has Niall of the 9 Hostages for the nine countries subdued and made tributary.
1. Munster .
2. Leinster .
6. The Picts.
7. The Dal Riad
8. The Saxons
9. The Morini.
Niall had two wife’s and it is said to have had fourteen sons or twelve. Who founded their own families and dynasties in Ireland. His Reign and life ended in 404 A.D. ? assasinated by Eocha, son of Enna Cinsalach, King of Munster.
T.F. O'Rahilly in his book Early Irish History and Mythology writes: I think it very likely that Eochu, the alleged slayer of Niall, was originally the mythological personage of that name, the Sun God, who was also the God of lightning. In this sense Eochu arrow or spear, and the original tradition would have meant that Niall was killed by a flash or lightning. This view receives support from the fact that Nath I's death is attributed to lightning, for the legend of Nath I's appears as i have suggested , to have been modeled that of Niall. Later our euhemerizing historians attempted, not very successfully, to convert this Eochu into a historical figure. According to a poem attributed in LL to Cinaed ua hArtacain, Niall led seven expeditions across the sea. On the last of these Eochu of the Laigin slew him, out of love for the Saxons. His men brought his body home, fighting seven battles along the way.
T.F. O'Rahilly also writes His relationship to his 'brothers' Fiachra, Brion and Ailill, all three of them connected with Connacht, must also be treated with considerable scepticism. Brian , for instance would appear to have lived a generation or two later that Niall's time. Indeed when the early pedigree makers decided to make the three Connachtmen brothers of Niall, they apparently had some qualms about it, for they admit that Niall had a different mother, Caireen .
" the most formidable onslaught had come from Ireland under one powerful leader acting in co-operation with the Picts and Saxons." - Roman Historian Claudian