Pope John XV

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.

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

[2] However, Joseph Brusher finds this unproven, as John XV had little authority in Rome at that time.

[3] Through his legate Leo, he mediated a dispute between King Ethelred the Unready of England and Duke Richard the Fearless of Normandy.

This affair is sometimes read as an early groundswell of the conflicts between popes and the Capetians, new kings of France, that came to a head later in the Investiture Controversy.

[3] At the synod, Bishop Arnulf of Orléans accused Pope John XV: Are any bold enough to maintain that the priests of the Lord all over the world are to take their law from monsters of guilt like these—men branded with ignominy, illiterate men, and ignorant alike of things human and divine?

As for Gerbert, he set out for the imperial court at Magdeburg and became the preceptor to Emperor Otto III.