[1] The Chronicle of the Princes records Einion assisting King Iago of Gwynedd in driving the Irish and their Danish allies from Wales in 966.
[2] A third raid in 976[3] went little better: Einion is recorded devastating the area so thoroughly it provoked famine but Owain ap Morgan's brother Ithel defeated him and restored the plunder to its owners.
[2] At some point, he seems to have annexed Brycheiniog for Deheubarth and King Hywel of Gwynedd—with the support of Ælfhere of Mercia[4]—then invaded in 980 and 981.
[2][5] Einion defeated them at Llanwenog and in Brycheiniog but the country was heavily despoiled by the northerners and the English and by a Viking raid against St. David's in 980[2] or 982.
[6] Einion predeceased his father, being slain at Pencoed Colwynn by the men of Glywysing and Gwent in AD 982[2] or 984.