14th century lead bulla found in Polish castle

Archaeological excavations at Człuchów castle in Poland have unearthed a 14th century lead bulla of Pope Gregory XI, a seal used to authenticate documents. The bulla is believed to have originated during the Teutonic Order's crusade against pagan Lithuania.

The bulla depicts "the faces of two men, separated by a cross, and on top the letters SPA*SPE, referring to the Saints Peter and Paul." The reverse side has the inscription *GREGORIUS*PP*XI*.