Gregory's name appears for the first time in an Arbroath Abbey document dating between 1189 and 1198, when he is holding the office of Archdeacon of Brechin.

[4] During Gregory's time the cathedral was run by Scottish priests called Céli Dé, governed until at least the early part of Gregory's episcopate by a prior named Máel Brigte (Mac Léoit, "MacLoud").

[5] The old abbots of Brechin were in the process of becoming the secular Mac in Aba (filius Abbe, "MacNab") lords of Glen Esk.

[6] Soon after Gregory's death these priests "by change of name" came to be "styled as canons".

[8] Gregory died sometime between his last appearance in 1242, and 1246 when the papacy mandated the confirmation of his successor Albin.