Sechnassach [SEP] father
Sechnassach
Sechnassach mac Blathmaic (died 671) followed his father Blathmac mac Áedo Sláine (died 665) and uncle Diarmait mac Áedo Sláine (died 665) as High King of Ireland and King of Brega. He belonged to the Síl nÁedo Sláine kindred of the southern Uí Néill, named from his grandfather Áed Sláine (died 604).
Sechnassach's father and uncle are said to have died in a great plague—the "buide Chonaill"—which struck Ireland from 664 or 665 onwards.
While the "Baile Chuinn Cétchathaigh
Sechnassach mac Colggen
Sechnassach mac Colggen (died 746/747) was a king of the Uí Cheinnselaig of South Leinster or Laigin Desgabair. He was of the Sil Chormaic sept of this branch of the Laigin. His father Colcú mac Bressail (died 722) was called king of Ard Ladrann (near Gorey, Co.Wexford) at his death obit in the annals in 722 which mention that he was killed. Sechnassach was the great-great grandson of Crundmáel Erbuilc (died 655),a King of Leinster and brother of Áed mac Colggen