A lead bulla or papal seal from the wreck of the 1622 galleon Nuestra Señora de Atocha. Papal bullae are seals that verify the authenticity of documents issued by a pope (papal bulls). They are attached to the vellum document by a hemp or silk cord. Typical papal bulls bearing a bulla would be grants, privileges, or personal indulgences. The obverse bears the name of the pope who issued the bull, and the reverse shows the likenesses of St. Peter and St. Paul. The Atocha bulla was issued by Pope Gregory XIII, who headed the Catholic church from 1572-1585. It is 3.9 centimeters in diameter; the cord that attached it, as well as the vellum bull, were deteriorated by the sea long ago.