Today is the Feast of St. Eusebius Sophronius Hieronymus, better known as St. Jerome of Stridonium, Priest and Doctor of the Church. Jerome apparently never wanted to be a priest; he seems to have been ordained under heavy pressure from the bishop, and only have consented when promised he could continue doing what he wanted to do, which is living the ascetic life in the desert. After ordination, he studied under St. Gregory Nazianzen and then served as secretary to Pope St. Damasus; he got into extraordinary trouble in the latter gig, because he was unsparing in his criticism of everybody. This trait won many for the ascetic life, especially among the upper class women of Rome, but after the death of Damasus, he was accused of an improper relationship with a widow, and had to leave. He then studied in Alexandria under St. Didymus the Blind, finally arriving at his hermit's cell near Bethlehem, where for decades he wrote the works that have most made him famous. He also continued his practice of sharp criticism, which among other things led at one point to a band of Pelagians breaking into the monastic buildings in which he lived and setting fire to them.
Calling him 'The Thunderer' is not an old custom; it derives from a poem in the 1950s by Phyllis McGinley, which was turned into a very catchy blues song by Dion DiMucci, which made the designation famous.