Lucius Coelius Firmianus, a celebrated author at the beginning of the 4th century, was, according to Baronius, an African; but, according to others, was born at Fermo in the marquisate of Ancona, from whence it is imagined he was called Firmianus. He studied rhetoric under Arnobius; and was afterwards a professor of that science in Africa and Nicomedia, where he was so admired, that the emperor Constantine chose him preceptor to his son Crispus Caesar. Lactantius was so far from seeking the pleasures and riches of the court, that he lived there in poverty, and, according to Eusebius, frequently wanted necessaries. His works are written in elegant Latin. The principal of which are, 1. De ira divina. 2. De operibus Dei, in which he treats of the creation of man, and of divine providence. 3. Divine Institutions, in seven books: this the most considerable of all his works: he there undertakes to prove the truth of the Christian religion, and to refute all the difficulties that had been raised against it; and he boldly, and with great strength, attacks the illusions of Paganism. His style is pure, clear, and natural, and his expressions noble and elegant, on which account he has been called the Cicero of the Christians. There is also attributed to him a treatise De morte persecutorum; but several of the learned doubt its being written by Lactantius. The most copious edition of Lactantius's works is that of Paris in 1748, 2 vols. 4to.