Lucius Caecilius Firmianus signo Lactantius (c. 250 – c. 325) was an early Christian author who became an advisor to Roman emperor, Constantine I, guiding his Christian religious policy in its initial stages of emergence, and a tutor to his son Crispus. His most important work is the Institutiones Divinae ("The Divine Institutes"), an apologetic treatise intended to establish the reasonableness and truth of Christianity to pagan critics.
He is best known for his apologetic works, widely read during the Renaissance by humanists who called Lactantius the "Christian Cicero". Also often attributed to Lactantius is the poem The Phoenix, which is based on the myth of the phoenix from Oriental[clarification needed] mythology. Though the poem is not clearly Christian in its motifs, modern scholars have found some literary evidence in the text to suggest the author had a Christian interpretation of the eastern myth as a symbol of resurrection.