A tanner was a craftsman who processed animal hides into leather through scraping, treating, and curing. The occupation required regular contact with dead animals and their skins, rendering tanners ceremonially unclean according to Jewish purity laws. Peter's willingness to lodge with Simon the tanner in Joppa signals an important shift in his understanding of ritual purity—a preparation for his vision on the rooftop and subsequent visit to the Gentile Cornelius. The occupation's social marginalization makes Peter's choice of accommodation theologically significant.