Lead, 40.47 grams, 38.38 dia, approx 5mm thickness. 13th century AD. A lead seal from a document issued by Pope John XXI. The iconography of papal bulls has not altered since the time of Pope Pasquale II (1099-1118) - one face bears the name of the issuing Pope and the other the opposed profile heads of SS. Peter and Paul with a cruciform emblem between and a form of the identifying abbreviated legend 'SPASPE', (Sanctus Petrus Sanctus Paulus 'Saint Peter, Saint Paul') on the other. The present example shows on the recto the faces executed in low relief in a realistic style within a border of fine dots, below the legend (partly lost in the crease) and on the verso the text '+/IO/HANNES/PP/XXI' with a superscript line above the 'PP'. There is some creasing above the images of the saints but otherwise the bull is in very fine condition.

The papacy of John XXI was short-lived, and held much promise which his untimely death curtailed. Petrus Juliani (or Petrus Hispanus as he was also known) was born in Lisbon, Portugal, around 1220 AD. He studied at the university of Paris under Albertus Magnus, and took a special interest in natural philosophy and medicine which he pursued as professor of medicine at the university of Siena, where he wrote the Summulæ logicales, which remained for almost three hundred years the classic textbook on logic. Petrus pursued a career in the church in various positions and made the acquaintance of Teobaldo Visconti so that when, in 1272, Teobaldo came to Viterbo after his election to the papacy as Gregory X, he appointed Petrus Hispanus his physician. Petrus's reputation as a physician and theologian grew, and he was appointed Archbishop of Braga in 1273. Gregory X's two successors in the papacy, Innocent V and Adrian V, each ruled for only a short time. After the death of Adrian V, Petrus Juliani was chosen pope, and crowned as John XXI. He intervened in the rivalries of the French crown to avoid conflict, and also sent several official letters to the court of Edward I of England demanding the arrears of tribute and attempting to secure the release of Eleanor, Countess of Montfort, and her brother Amaury whom Edward was holding for ransom. In pursuit of his academic interest, John XXI had a separate apartment built onto the palace at Viterbo, where he could retire to private study; on 12th May 1277 the apartment collapsed, trapping him in the ruins. Although he lived for a few days after his rescue, he died from the injuries sustained. After his death, tales began to circulate of the pope's dabbling in magical arts in his private room and that the destruction was caused by an act of God in punishment for this sin.