John XV

Pope John XV is mentioned in the Dagome iudex, one of the earliest written records of the nation of Poland. Pope John XV (, ; died March 996) was the bishop of Rome and ruler of the Papal States from August 985 until his death. A Roman by birth, he was the first pope who canonized a saint. The origins of the investiture controversy stem from John XV's pontificate, when the dispute about the deposition of Archbishop Arnulf of Reims soured the relationship between the Capetian kings of France and the Holy See.

Early life John XV was the son of Leo, a Roman presbyter. Before he became pope in August 985, John was cardinal-priest of St. Vitalis.

Pontificate John XV's venality and nepotism allegedly made him very unpopular with the citizens of Rome.

John was a patron and protector of the reforming monks of Cluny. Through his legate Leo, he mediated a dispute between King Ethelred the Unready of England and Duke Richard the Fearless of Normandy.

The proceedings of the Synod of Reims were repudiated by Rome, although a second synod had ratified the decrees issued at Reims. John XV summoned the French bishops to hold an independent synod outside the French king's realm at Aachen to reconsider the case. When they refused, he called them to Rome, but they protested that the unsettled conditions en route and in Rome made that impossible. The Pope then sent a legate with instructions to call a council of French and German bishops at Mousson, where only the German bishops appeared, the French being stopped on the way by Hugh Capet and his son Robert. Through the exertions of the legate, the deposition of Arnulf was finally pronounced illegal. After Hugh Capet's death on 23 October 996, Arnulf was released from his imprisonment and soon restored to all his dignities. As for Gerbert, he set out for the imperial court at Magdeburg and became the preceptor to Emperor Otto III.

Death In 996, Otto III undertook a journey to Italy to obtain an imperial coronation from the pope, but John XV died of fever in March 996, while Otto III lingered in Pavia until April 12 to celebrate Easter. The emperor then elevated his own cousin Bruno to the papal dignity under the name of Gregory V.