Saint Gregory was the foremost influence in shaping the early medieval papacy, drawing on The City of God by Augustine of Hippo for his theological foundation. Strongly involved with monasticism, Pope Gregory the Great also reformed the mass, and was named a Doctor of the Church. He has been credited with originating Gregorian Chant, although it is more likely that others developed it in keeping with his new rules for the mass.
Born of an eminent family, Gregory is believed to be the grandson of Pope Felix III. He attained the office of praefectus urbis ("urban prefect," the administrative president of Rome) at the age of 32, but had to give it up after only two years. He then turned his attention to his lifelong interest in monasticism. After converting a palace he had inherited at Caelian Hill, Rome, into St. Andrew's Monastery (without, however, becoming its abbot), Gregory used the rest of his considerable fortune to turn his holdings in Sicily into six more monasteries.
Pope Benedict I then appointed Gregory as a deacon in Rome, and in 579 he was sent by Pope Pelagius II to Constantinople as a papal representative. There, under emperors Tiberius II and Maurice, he attempted to procure aid for Rome against the Lombard invaders, with little success. In 585 or 586 he was recalled to Rome, where he happily took up the post as Abbot of St. Andrew's.
In early 590, after a year of floods and plague capped by the death of Pelagius, Gregory was unanimously selected as the next pope.
He appears to have been sincere in his protestations against the election, for he loved the monastic life. But once he took office he devoted himself to his duties with great energy and determination.
Gregory worked hard to alleviate the suffering of the people, finding shelter and food for refugees from the Lombard invaders as well as plague and flood victims, and using revenues from Church property to aid the poor and the starved. He also centralized the papacy's administrative machinery and fought corruption and negligence. In an attempt to save the Italian Church, Gregory began to Catholicize the Arian Lombards and struggled to stop the war-mongering governor of Ravenna from fighting them, managing to establish a fragile peace in 598.
In 602 a Thracian centurion in the imperial army by the name of Phocas overthrew Emperor Maurice and had him and his family exectued. Charismatic and manipulative, Phocas deceived Gregory into supporting him, mainly because of the emperor's conciliatory attitude toward the Lombards and an appearance of subordination to the papacy. This support for a secular leader was a precedent that many future popes would follow.
Another precedent Gregory would set was a degree of militance in his approach to evangelization of the barbarian tribes. This willingness to use force to convert the heathen would later be interpreted as a kind of "holy war." On the other hand, his attitude toward Jews was one of tolerance, though his evangelism moved him to offer economic advantages to converting.
Gregory appeared to understand that the Barbarians who had been migrating throughout Western Europe and establishing kingdoms were the future of the Catholic Church. He sponsored enormously successful missions in England, which would later facilitate missions on the continent, and continued close negotiations with the Lombards.
A successful organizer, missionary and reformer, Gregory was able to consolidate the lands controlled by the papacy into what would later be known as "the Papal States." Ironically, these lands would serve as the basis of expansion and imperialism on the part of later popes, a concept that was diametrically opposed to the views of Gregory, who remained a monk at heart.
Who's Who Profile of Pope Gregory I