John was born in Rome, the son of a priest named Leo. He ascended to the Chair of Peter over a year after Pope John XIV died, given that it took nearly that long to get the antipope, Boniface VII, off his phony throne (he died in July 985). In the meantime, a man named Crescentius, a relative of Rome’s former ruler Alberic II, had taken charge of the city. That spelled bad news for John XV who, once elected in August 985, was marginalized by Crescentius to manage little more than the Church’s affairs. John eventually fled to Tuscany and sought the help of Emperor Otto III because of Crescentius’ tyranny. Sounds like it was a long decade for John XV. He died April 1, 996.

Pope John XV is known for making history whose effects are still being seen today. On January 31, 993, John convened a meeting of bishops in the Lateran Palace to formally canonize Ulrich, the former Bishop of Augsburg who had died 20 years earlier. It was the first time in Church history that a pope canonized a saint by way of a solemn ceremony, beginning a new tradition that, up to that point, had primarily consisted of the deceased person being venerated after death by popular acclaim (Think: “Bob was holy. Like, really holy. We should ask for his prayers.”). John’s act laid the foundation for the canonization process we know and love today. 

Fun fact: Pope John XV is sometimes referred to in papal lists as John XVI, due to what may have simply been a clerical error. A few papal historians in the old days had mistakenly added an additional “Pope John” after the antipope Boniface VII, claiming that he had reigned four months, and thus referred to the real John XV as “Pope John XVI”. The error has since been cleared up.