Bishop Firmilian of Caesarea (Kayseri, d. 269)

Firmilian served as bishop of Caesarea for 37 years, from 232 to 269. He was a contemporary of bishop Gregory the Wonder-Worker of Neocaesarea (modern Niksar). Basil the Greatused Firmilian’s book on the Holy Spirit, titled Logoi, as a resource when he wrote his book On the Holy Spirit.