 After the death of Gilbert de Greenlaw, Bishop of Aberdeen, in 1421, Lichton was chosen as his successor, and was translated to the diocese of Aberdeen in early April 1422, on the authority of Pope Martin V. Pope Martin delegated authority to Robert de Cardeny, Bishop of Dunkeld, and William Stephen, Bishop of Dunblane, in order to take Lichton's oath to the Papal see without forcing him to travel to Rome. It is of note that Lichton had already been in possession of the prebend of Kinkell in the Aberdeen diocese, a former possession of the Knights Hospitaller but attached to Aberdeen Cathedral by Lichton's time.
