Today is the commemoration of Pope Gregory the Great, one of the shapers of medieval Christianity. A member of an old senatorial family who rose to the top of the imperial hierarchy in Rome, he withdrew from public service, founded a monastery in one of his family’s homes in Rome. But his education and diplomatic expertise pressed him into service as a papal legate to the Emperor in Constantinople. He returned to Rome and was acclaimed pope in 591.

Among his achievements: the mission of St. Augustine of Canterbury to England, liturgical revision (the common name for medieval chant “Gregorian” chant bears his name). He was  profound theologian, exegete, and pastor. His On Pastoral Care shaped the ministry, his Moralia in Job a model of biblical scholarship for centuries. He used his family’s wealth to feed the Roman people during famine and pestilence, and his administrative skill secured papal primacy in the west.

Among the most popular legends of Gregory in the later Middle Ages was the story that once as he was celebrating mass, he heard someone deny transubstantiation. Praying for a sign to prove the reality of the bread and wine becoming Christ’s body and blood, suddenly an image of the crucified Christ appeared before him and all the people. Here’s artist’s rendering of that legend: