Aindréas was a native Scot, and very likely came from a prominent family in Gowrie, or somewhere in this part of Scotland.
[1] At some stage in his career, he was a monk of Dunfermline Abbey (see below), though it is not known if this was before or during his period as bishop of Caithness.
It is probably no coincidence that the erection of the Scottish diocese of Caithness, and imposition of a Gaelic bishop, coincided with the introduction of Harald (Aralt), son of the Earl or Mormaer of Atholl Matad, as ruler of the formerly Norse-ruled province.
Bishop Aindréas is a frequent witness to the charters of Kings David I, Maol Caluim IV and William I.
[4] The author of the early 13th century historical tract known as de Situ Albanie (En: On the Place of Scotland) cites Aindréas as a source for his second list of Pictish kingdoms, and describes him as "a trustworthy informant ... a venerable man, bishop of Caithness, by nation a Gael (nacione Scoctus) and monk of Dunfermline".