Physician and Courtier
The sources present Caesarius as a man of exceptional learning who attained worldly distinction without renouncing his faith. After his medical studies at Alexandria, his skill brought him to Constantinople and into the imperial court. According to the tradition, his reputation was such that he was sought as a personal physician, and he held his place at court through several reigns.
His service under Julian the Apostate was a particular concern to his Christian family, given the emperor's hostility to the faith. The accounts relate that Julian pressed him to abandon Christianity and adopt paganism, but failed, and that Caesarius remained unharmed. Under Valens he held a financial office connected with the province of Bithynia, described in the sources as a treasury and tax-collection position.