Pope Zachary died in the middle of March, 752 after a reign of ten and a half years, leaving the Lombard warriors reaching out to win the Italian peninsula. An election on March 23 gave the papacy to Stephanus. This man was a cardinal-priest of San Grisogono, a post he had held since 745 when Zachary had appointed him to the position. Unfortunately, within three days, Stephanus succumbed to a stroke, before ever being consecrated. Thus, according to some, he, technically,, was never a pope.
Within three days, a Roman Cardinal-deacon, also named Stephanus, was consecrated. His reign began March 26, 752. This Pope Stephen (to use the Anglicized form) is considered to be the end of the Byzantine Papcy and the beginning of the Frankish Papacy.
After the Lombard King Ratchis abdicated in 749, partly due to his friendship and tolerance of the Romans, his brother Aistulf, Duke of Friuli, became the new Lombard king. Aistulf was nowhere near as friendly to Rome as was his older brother. He had a more aggressive policy of expansion and raids against the Roman duchy and Ravenna. Remember, Ravenna was the center for Byzantine control of the Italian peninsula. While Pope Zachary was still alive, Aistulf conquered Cornacchio and Ferrara in 750. The next year, he took Ravenna and Istria and threatened the Roman duchy with high taxes.
Stephen turned to Emperor Constantine V, in Constantinople. The emperor had his hands full with the Muslim Caliphate attacking from the south and the Bulgars attacking from the north. The best the emperor could do was to send a message to the tone of “Get another Germanic tribe to attack the Lombards”. Alarmed, to say the least, at the imminent danger his home was in, Pope Stephen turned to the Carolingian mayors or Austrasia, what is now northeast France and some of western Germany. The mayor was Pepin the Short, son of the hero Charles Martel and usurper of the throne of the Franks. Pepin tried to help by offering diplomatic means out of this problem. Aistulf was not interested.
Pope Stephen had no alternative than to cross the Alps and visit with Pepin, himself. He arrived in January, 754 and was welcomed most heartly. After months of negotiations, in July, Stephen consecrated Pepin and his sons as kings of the Romans. For this backing, Pepin promised to fight Aistulf and win back the land due to the Church. What land seemed to be listed in a forged document that was being passed around at the time, the “Donation of Constantine”.
As soon as the passes through the Alps opened up in 755, Pepin fulfilled his promise and fought Aistulf. A first treaty was signed in June and the lands were to be returned to Constantinople. But, once the Franks went home, Aistulf’s army surrounded Rome through the winter of 756. Once again, as soon as the passes through the Alps opened, Pepin and the Franks returned and defeated Aistulf.
The taken land was returned to the duchy of Rome and to the exarchate. The Lombard king was allowed to return to his land. But the pope now owned the duchy of Rome and a huge swath of land crossing the entire peninsula, including the land previously controlled by the Byzantine exarchate. Constantinople lost all the land it owned in Italy. This made the pope independent of Constantinople. He was essentially a sovereign prince.
However, that is not the end of the story. Aistulf died in an accident in late 756. His brother, Ratchis, the king who abdicated, decided to leave his monastery and try to re-win his crown. He did get a military force together and won Pavia. However, a coalition of Pope Stephen, Pepin and the Duke of Tuscany stopped him. The pope talked to Ratchis about renouncing his monastic vows and the ex-king returned to Monte Cassino.
Thinking that everything was under control, the pope had to develop a governmental structure for his new holdings. He named archbishop Sergius of Ravenna as governor. In no time, the archbishop started a rebellion. Pope Stephen had him arrested and brought to Rome to be detained.
Politics was not all that Stephen was involved in. He kept up a conversation with the emperor regarding restoring images into the worship life of the people of the Eastern Empire, encouraging him. In addition, Stephen was concerned about the health of the poor in Rome and had hospitals built near St. Peter’s for them.
Pope Stephen died April 26, 757. He was buried in St. Peter’s Basilica.