The first mention of Cenn Faeled in the annals is in the year 653 when the ally of the Ui Fiachrach Aidhne, Marcán mac Tomaini, the king of the Ui Maine was slain in battle in Iarthair Seola by Cenn Fáelad and Máenach mac Báethíne of the Ui Briun. A step in the expansion of the Ui Briun from the plains of Mag nAi. In the Annals of the Four Masters it is Maenach who is referred to as chief of the Ui Briun.
The next mention of Cenn Faeled is in 663 when the Annals of Tigernach mention that he became king of Connacht in succession to Guaire Aidne mac Colmáin(d. 663). The king lists such as that in the Book of Leinster also place his reign after Guaire.. However, the Chronicum Scotorum mentions the death of Muirchertach Nár mac Guairi(d. 668) as king of Connacht in 668. The annals also mention a certain Dub-Indracht mac Dúnchada as king of the Ui Briun of Mag nAi in 666.
The last mention of Cenn Faeled in the annals is in 682 when he was killed by one of the Conmaicne Cúile, a subject tribe of the Seola region. A killing which reflected the Ui Briun policy of subjugation and annexation of subject tribal territories.. His descendants were sometimes titled kings of Iarthair Connacht in the annals.