His pontificate was marked by rapid political shifts, with Benevento successively under Byzantine (891–895), Spoletan (895–897) and Lombard rule.
[4] The Byzantine strategos George led the Beneventans in an attack on Salerno in 894, expecting some Salernitan exiles to open the gates for them.
Peter, who had accompanied him not knowing the plan, advised him that if his men entered Salerno they would all die, and the spooked Byzantines duly retreated.
[5] Peter, in the narrative of the Catalogus regum Langobardorum et ducum Beneventanorum, stood against the oppressiveness of Byzantine rule after George.
In August 895, he urged the people to open the gates to Duke Guy IV of Spoleto, whose mother, the Empress Ageltrude, was a Beneventan.
[6] According to the short Continuatio codicis Vaticani, covering the years 890–897, when the Byzantines abandoned the city as the Spoletans approached, they refrained from harming it because it was under the care of Bishop Peter.
According to the Catalogus, at the instigation of "jealous men" (invidis viris) Guy had him imprisoned for four months before exiling him to Salerno, where he was placed in the charge of Prince Guaimar I.
This proved deeply unpopular, and Guy soon had to bring back the bishop, to much commotion and rejoicing, in the words of the Catalogus.
[8] Radelchis was regarded as a fool by the people and, taking advantage of the situation, Count Atenulf of Capua deposed, imprisoned and finally exiled him in November or December 899.
A similar popular revolt had put Bishop Athanasius II of Naples on the ducal throne of his city in 878.