Saint Emygdius (d. c. 309 AD) was a Christian bishop who is venerated as a martyr. Tradition states that he was killed during the persecution of Diocletian.
His legend states that he was a pagan of Trier who became a Christian. He traveled to Rome and cured the paralytic daughter of his host Gratianus, who had let him stay with him at his house on Tiber Island. Gratianus' family then converted to Christianity.
Emygdius also cured a blind man. The people of Rome believed him to be the son of Apollo and carried him off by force to the Temple of Aesculapius on the island in the Tiber, where he cured many of the sick. Emygdius declared himself a Christian, however, and tore down the pagan altars and smashed into pieces a statue of Aesculapius. He also converted many to Christianity; this enraged the prefect of the city.
He was made a bishop by Pope Marcellus I (or Pope Marcellinus), and sent to Ascoli Piceno.
On his way to Ascoli, Emydgius made more conversions, and performed a miracle where he made water gush out of a mountain after striking a cliff. Polymius, the local governor, attempted to convince Emygdius to worship Jupiter and the goddess Angaria, the patroness of Ascoli. Polymius also offered him the hand of his daughter Polisia. Instead Emygdius baptized her as a Christian in the waters of the Tronto, along with many others.
Enraged, Polymius decapitated him on the spot now occupied by the Sant'Emidio Red Temple, as well as his followers Eupolus (Euplus), Germanus, and Valentius (Valentinus). Emygdius stood up, carried his own head to a spot on a mountain where he had constructed an oratory (the site of the present-day Sant'Emidio alla Grotte). After Emygdius' martyrdom, his followers attacked Polymius' palace and pulled it down.