Physician, younger and only brother of Gregory of Nazianzus, born probably c. 330 at Arianzus, near Nazianzus; died at the end of 368 or the beginning of 369. He received a careful training from his saintly mother Nonna and his father Gregory, Bishop of Nazianzus. He studied probably at Caesarea in Cappadocia, and then at the celebrated schools of Alexandria. Here his favorite studies were geometry, astronomy, and especially medicine. In the last-named science he surpassed all his fellow students. About 355 he came to Constantinople, and had already acquired a great reputation for his medical skill, when his brother Gregory, homeward bound from Athens, appeared there about 358. Caesarius sacrificed a remunerative and honorable post and returned to his parents with Gregory. The capital, however, soon proved to be too great an attraction for him; we find him occupying an exalted position as physician at the court of Constantine and, much to the regret of his family, at that of Julian the Apostate. Julian failed in his efforts to win him over to Paganism. Caesarius, more appreciative of his faith than of imperial favor, ultimately left the court, but returned to Constantinople after Julian's death. Under the Emperor Valens he became quaestor of Bithynia. His remarkable escape from the earthquake which shook Nicaea (11 October, 368) induced him to heed the insistent appeals of his brother and St. Basil, who urged him to leave the world. He was suddenly seized with a fatal illness, shortly after having received baptism, which he, like many others at the period, had deferred until late in life. He was unmarried, and directed that all his goods should be distributed to the poor, an injunction which his servants abused in their own interests. His remains were interred at Nazianzus, where his brother pronounced the funeral oration in the presence of his parents.
The admission of the identity of this Caesarius with his namesake, the Prefect of Constantinople, who, in 365, was thrown into the prison by Procopius, rests on an assumption of James Godefroy, the editor of the Theodosian Code (Lyons, 1665), and not on any solid historical ground. The four "Dialogues" of one hundred and ninety-seven questions and answers which go under his name, and are to be found in Migne, P.G., XXXVIII, 851-1190, can hardly be from his pen, owing to their nature, contents, and anachronisms. Today they are generally looked upon as spurious.
Greg. Naz. in P. G., XXXV. 751-88; BIRKS and CAZENOVE in Dict. Christ. Biog., s. v.; BARDENHEWER, Patrologie (Freiburg, 1901), 257; VERSCHAFFEL in Dict. de théol. cath. (Paris, 1905), II, 2185-86. N.A. WEBER
Cf. The Catholic Encyclopedia, Volume III (1908, 1910, 1911)