He was highly praised by Humbert de Romans, Bernard Gui, Antonio Pierozzi, Leander Alberti, and Thomas Malvenda in his Annals.
In 1247 Pope Innocent IV appointed Reginald Archbishop of Armagh and Primate of Ireland, perhaps on account of his knowledge of the English language, but also as a check on the power of Henry III of England over the Irish church.
Two other Dominicans, David McKelly, Archbishop of Cashel, and Alan O'Sullivan, Bishop of Cloyne, already held posts in Ireland and may have influenced Innocent's choice of Reginald to replace the abdicating Albert Suerbeer.
The Irish Annals of Ulster state that the bishop of Raith Luraigh (now the diocese of Derry) was appointed as Albert's successor, indicating that Reginald was already serving in Ireland.
[1] In 1252 Reginald paid his ad limina to Innocent IV, but was detained in Rome for a long period of time litigating on behalf of his diocese, which cases he eventually won.