Stephanus was born around 720 in Sicily, the son of Olivus, a man of Greek descent. As a young man, he traveled to Rome and joined the monastery of St. Chrysogonus. From there he became a Benedictine monk. He worked in the Lateran Palace during the reign of Pope Zachary and was ordained at that time. Stephanus worked his way up the ranks of officials and was probably a close friend of Pope Paul I, since he spent time with the dying pontiff.
As Paul died, in the summer of 767, various factions, not happy with Paul’s policies, decided to hoist their own candidates onto the throne. First the Tuscan nobles, under the leadership of Duke Toto of Nepi, voted in Toto’s brother, Constantine, a layman. The Lombard king, Desiderius sent an army to Rome, killed Toto and sent Constantine away. They replaced him with their own candidate, Philip.
Christopher, head of notaries, and his son, Sergius, treasurer of the Church, forced out Philip. Constantine was captured. Christopher organized a canonical election, summoning laity, nobles and clergy. On August 1, Stephen was elected, acclaimed as the pope-elect and escorted to the Lateran.
Somehow, the supporters of Stephen attacked Constantine and his supporters, chased and captured the anti-pope. He and several of his followers were tortured and blinded. Stephen was crowned on the 7th of August 768.
The town of Alatri, hearing of the election, revolted. Stephen’s supporters went in and tortured the leaders. Constantine was blinded and put out on the streets of Rome, with instructions that he not be helped. A supporter of Philip, Waldiput, was arrested, blinded and died on charges of conspiring to kill Stephen.
No one knows the role that Stephen played in this chaos. It is apparent that the Papal States were a large part of the cause, making rivalry between various factions for control of the land.
When all was again under control, the following year, Stephen called for a council. Charlemagne sent twelve bishops to represent the Frankish kingdom. At this Lateran Council, experience showed Pope Stephen that future elections had to be controlled. Strict rules were written for future elections. Also, devotion to icons was confirmed. In addition, all the appointments made by Constantine were considered null and void and the anti-pope, himself, was placed in a monastery.
In keeping with the newly chosen rules of elections, Stephen was tested the very next year. A layman, Michael, was nominated to be archbishop of Ravenna, to overthrow Leo, the duly nominated archbishop. Stephen had to resort to Frankish ambassadors and papal legates working towards an overthrow to get Leo consecrated.
At the same time, Stephen was worried about the expansionist plans of the Lombards in northern Italy. The pope had to intervene between the two Frankish brothers, Charlemagne and Carloman, who were feuding. He then asked them to intercede with the Lombards on his behalf. Charlemagne sent an embassy, with his mother, Bertrada of Laon, in a lead position. Stephen received back the disputed land of Benevento.
However, then King Desiderius and Bertrada had a discussion about marrying Desiderius’ daughter Desiderata and one of Bertrada’s sons. They may have also discussed the marriage of Bertrada’s daughter, Gisela to Desiderius’ son Adalgis. This would give a double bond between the Franks and the Lombards. The only problem was that both Carloman and Charlemagne were already married. Also, if they followed through, the Franks would be going against the promises to support the pope. That argument did not prevent Charlemagne from marrying Desiderata in 770.
As the negotiations between the Franks and the Lombards went on, Stephen’s supporters, Christopher and Sergius, were pro-Frank and anti-Lombard. Desiderius was anxious to win Stephen to his side. He bribed the papal chamberlain to spread rumors about the father and son to the pope.
The next year, Desiderius approached Rome with with an army, proclaiming himself to be on pilgrimage. Christopher and Sergius, not wanting him in, closed the gates to the city and stationed arms troops at the wall. Desiderius asked for the pope to come to him. As the pope left the palace, the chamberlain and his associates tried to stir up a riot. The riot was quelled and the rioters were forced to the Lateran. Stephen saw it. There was a complete misunderstanding. Christopher, thought that Stephen was in the Lombards’ grip. Stephen went to St. Peter’s Basilica the next day. Desiderius took the pope into custody and demanded Christopher and Sergius in exchange. The king received both men whom he tortured and imprisoned.
In the few years left, Stephen was in a three-way ploy with the Lombards and the Franks. In early 772, Stephen was ill. The chamberlain, the same man, took advantage of the situation in that he exiled clergy and nobles from Rome and imprisoned others. Sergius, Christopher’s son, was taken from his prison and killed. The city was in chaos when Stephen died at the end of January or beginning of February, 772.