Níall of Carrick was the second man to bear the title Mormaer, or Earl, of Carrick. He was successor of mormaer Donnchadh of Carrick. Originally he was believed to be the son of Donnchadh, however, it is now believed that he was more likely his grandson, the son of Donnchadh's oldest son and heir Cailean mac Donnchadh. Cailean, also known as Colin and Nicholaus of Carrick, predeceased his father and therefore upon Donnchadh's death in 1250, the title of Mormaer came to Niall. It has been suggested that Cailean's wife, Niall's mother, was a daughter of Niall Ruadh, briefly king of Tir Eoghain. Niall's grandfather Donnchadh held lands in Ireland, such a marriage of his son would have reinforced Donnchadh's Irish alliances and would account for the use of the name Niall. It would also explain the strong alliance with the Ó Neill held by Niall's grandsons. As the son of Cailean, Niall had one sister, Afraig, who married Gilleasbaig of Menstrie, a baron of Clackmannanshire who was the first attested man to bear the surname "Campbell".

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Níall of Carrick was the second man to bear the title Mormaer, or Earl, of Carrick. He was successor of mormaer Donnchadh of Carrick. Originally he was believed to be the son of Donnchadh, however, it is now believed that he was more likely his grandson, the son of Donnchadh's oldest son and heir Cailean mac Donnchadh. Cailean, also known as Colin and Nicholaus of Carrick, predeceased his father and therefore upon Donnchadh's death in 1250, the title of Mormaer came to Niall. It has been suggested that Cailean's wife, Niall's mother, was a daughter of Niall Ruadh, briefly king of Tir Eoghain. Niall's grandfather Donnchadh held lands in Ireland, such a marriage of his son would have reinforced Donnchadh's Irish alliances and would account for the use of the name Niall. It would also explain the strong alliance with the Ó Neill held by Niall's grandsons. As the son of Cailean, Niall had one sister, Afraig, who married Gilleasbaig of Menstrie, a baron of Clackmannanshire who was the first attested man to bear the surname "Campbell".