 They belonged to a branch known as the Uí Felmeda descended from Fedelmid, son of Énnae Cennsalach.His son Óengus, grandson Muiredach, and great-grandson Eochu were all kings of the Uí Cheinnselaig.According to the "Book of Leinster," Brandub succeeded Áed Cerr mac Colmáin Már (died 595) of the Uí Dúnlainge as king of Leinster (actually Áed Dibchine mac Senaig of the Uí Máil)

In the "Rawlinson B 502 manuscript," dated to c. 1130, is the poem "Gein Branduib maic Echach ocus Aedáin maic Gabráin" ("The Birth of Brandub son of Eochu and of Aedán son of Gabrán").