On this day we celebrate the feast of Sts. Elias, Jeremias, Isaias, Samuel, and Daniel, Egyptian converts who were tortured and martyred in Caesarea in 310.
They had gone to visit and comfort the enslaved workers in the copper mines of Cilicia. On their way back, they were arrested at Caesaria and taken to Firmilianus, the governor. When asked their names, they gave the names they had received at baptism. When asked their country, they said Jerusalem, meaning their heavenly destination.
We know of these martyrs from Eusebius, Bishop of Caesarea. He related their story in his History of the Martyrs in Palestine. (Scroll down a third of the way to "The Confession of Paulus, and Valentina, and Hatha.)
Eusebius framed the story of Elias and his companions in a criticism of Jews, a recurring theme throughout his writings. The Father of Church History constantly disparaged Jews, whom he called "the circumcised".
--See Constantine and Eusebius, by Timothy D. Barnes, Harvard University Press, 2006. Search terms: Firmilianus, martyrs, Jews, Cilicia, circumcised.