He had been made bishop of Anagni by Pope Formosus. The circumstances of his election are unclear, he was sponsored by one of the powerful Roman families, the house of Spoleto, that contested the papcy at the time.
Stephen is remembered in connection with his conduct towards the remains of Pope Formosus, his last predecessor but one, whose rotting corpse he exhumed and put on trial in the Cadaver Synod (synod horrenda) in January 897. The corpse was found guilty, mutilated and quickly buried, it was then re-exhumed and thrown in the Tiber. All ordinations performed by Formosus were annulled.
The trial excited a tumult, which ended in Stephen's imprisonment and his death by strangling.
wikipedia.org dumped 2003-03-17 with terodump