Flavius Caesarius (Greek: Καισάριος; floruit 386–403) was a politician of the Eastern Roman Empire, who served under the emperors Theodosius I and Arcadius.
[4] Despite his merits, Caesarius was not appointed to higher offices in the following years, when Rufinus was in power as magister officiorum and praetorian prefect of the East.
Meanwhile, his younger brother Aurelianus made career, succeeding Rufinus as magister officiorum in 392 and then holding the office of praefectus urbi of Constantinople between 393 and 394.
Gainas chose Caesarius as successor to Aurelianus to the office of Praetorian prefect of the East, but, after a short time, he left Constantinople and was defeated by the magister militum per Orientem Fravitta.
The property had been left as legacy to the monks by Eusebia, a close friend of Caesarius' wife, who had asked them to bury the relics of the Forty Martyrs of Sebaste she kept in her house.