This pfennig from the 13th century features a double head below a tower and flanked by two lilies. In is a condominium issue of the mint of Breisach under the Bishop of Basel, perhaps Berthold II of Pfirt (1249-1262). The moneyer supposedly was the bishop's brother, Ulrich of Pfirt.
The double head (Janus head) represents the two patron saints of Breisach, St Gervasius und St Protasius.
The coin is rare. Most of the existing pieces are known from the coin troves of Malterdingen (26 specimens) and of Marbach (75 specimens). This coin is number 13 of the Marbach trove.