Throughout much of his reign, Énna acknowledged the overlordship of Toirdelbach Ua Conchobair, King of Connacht, although he participated in a failed revolt against the latter in 1124 before making amends.

[7] In the 1040s, the family seized possession of the provincial kingship of Leinster in the person of the King of Uí Chennselaig, Diarmait mac Máel na mBó, Énna's paternal great-grandfather.

[10] Énna and his immediate family were members of the Meic Murchada, a branch of the Uí Chennselaig descended and named after Diarmait mac Máel na mBó's son, Murchad.

[17] At some point afterwards, Énna apparently gained the kingship himself, as he is accorded the title rí Laigen ⁊ Gall by the Annals of Ulster in an entry recording his submission to Toirdelbach in 1122.

[29] His death there suggests that the Meic Murchada were patronising this Norse-Gaelic enclave,[30] and it appears that this town and Dublin were the primary concentrations of Leinster's wealth.