Antipope Boniface VII

Antipope Boniface VII (Latin: Antipapa Bonifatius VII; died 20 July 985), otherwise known as Franco Ferrucci, was a Catholic prelate who claimed the Holy See in 974 and from 984 until 985. A popular tumult compelled him to flee to Constantinople in 974; he carried off a vast treasure, and returned in 984 and removed Pope John XIV (983–984) from office. He is supposed to have put Pope Benedict VI to death. After a brief second rule, he died under suspicious circumstances. He is today considered an antipope.

Source: Wikipedia — https://en.wikipedia.org/wiki/Antipope_Boniface_VII