He had been made bishop of Anagni by Pope Formosus. The circumstances of his election are unclear, but he was sponsored by one of the powerful Roman families, the house of Spoleto, that contested the papcy at the time.
Stephen is largely remembered in connection with his conduct towards the remains of Pope Formosus, his last predecessor but one. Doubtless under pressure from the Spoleto contingent, the rotting corpse of Formosus was exhumed and put on trial, in the so-called Cadaver Synod (synod horrenda), in January 897. With the corpse propped up in a throne, a deacon was appointed to answer for the deceased pontiff, who was condemned for performing the functions of a bishop when he had been deposed and for receiving the pontificate while he was bishop of Portopassing from the See of Porto among other revived charges that had been levelled against Formosus in the strife during the pontificate of John VIII. The corpse was found guilty, stripped of its sacred vestments, deprived of two fingers of its right hand, clad in the garb of a layman, 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. Though the instigators of the deed may actually have been Formosus' enemies, Lambert of Spoleto and his mother Ageltruda, who had recovered their authority in Rome at the beginning of 897 by renouncing their broader claims in central Italy, the outrage ended in Stephen's imprisonment and his death by strangling that summer.
Pope Boniface VI
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