[1] Óengus, along with his brother, son Eogán, and nephew Domnall, is included in the Duan Albanach, a praise poem from the reign of Máel Coluim (III) mac Donnchada listing Máel Coluim's predecessors as kings of Scots, of Alba and of Dál Riata from Fergus Mór and his brothers onwards.
[2] However, it is now suggested that their inclusion is due to their importance in the religious communities of Dunkeld and St Andrews, where they were seen as founders and early patrons.
[4] Óengus died in 834, the only event of his reign reported in the Irish annals and was succeeded by his nephew Drest mac Caustantín.
Walter Bower in his Scotichronicon (1440s) supplies a legend according to which Saint Andrew appears to Óengus II in 832, on the eve of a battle against the Angles.
[6] Skene, in his notes to Fordun IV, xiii-xiv, states that the episode is placed in the 4th century, making the entire tale anachronistic in the extreme.