In May 1514, he took up a post as priest in the town of Braunschweig (Brunswick), where he was occupied on and off for the next few years. It was here that he began to question the practices of the Catholic Church, and to criticize, for example, the selling of indulgences. In letters of this time, he is already being addressed by friends as a "castigator of unrighteousness". Between 1515 and 1516, he also managed to find a job as schoolmaster at a nunnery in Frose, near Aschersleben.