(Φιλάδελφος), a surname of Ptolemaeus II. king of Egypt [PTOLEMAEUS II.], and of Attalus II. king of Pergamum [ATTALUS II.].
Philadelphus is also the name of one of the Deipnosophistae in Athenaeus, who calls him a native of Ptolemais, and describes him (i. p. 1) as a distinguished man in philosophical speculation and of an upright life.