(Σέλενκος), king of SYRIA, surnamed PHILOPATOR, was the son and
successor of Antiochus the Great. The date of his birth is not mentioned; but he must have
already attained to manhood in B. C. 196, when he was left by his
father in command of his forces at Lysimachia. in the Chersonese. with orders to rebuild that
city, which Antiochus designed, or affected to design, as a royal residence for Seleucus
himself (Liv. xxxiii. 41, 35.15, 36.7; Plb. 18.34;
Appian, Syr. 3). Again, in B. C. 190, we find
him stationed in Aeolis with an army, to keep in check the maritime cities. Here he succeeded
in reducing Cyme and other places, by voluntary submission, while he regained Phocaea by the
treachery of the garrison. Shortly after he took advantage of the absence of Eumenes to invade
his dominions, and even proceeded to lay siege to Pergamus itself; but the daring and repeated
sallies of Diophanes, a leader of Achaean mercenaries, who had thrown himself into the place,
compelled him to raise the siege and retire (Liv. 37.8, 11, 18, 20,
21 ; Plb. 21.4; App. Syr. 26). In the great battle against the Romans near Magnesia, in the same year,
Seleucus was entrusted by his father with the command of the left wing of his army, but was
totally defeated by Attalus, to whom he was opposed, and fled from the field of battle to
Apamea in Phrygia (Liv. 37.40, 43;
App. Syr. 33, 36). In the following year (B. C.
189), after the conclusion n of peace with Rome, he was sent by Antiochus to the
support of the consul Cn. Manlius, and not only furnished him with abundant supplies of corn,
but rendered him active assistance on more than one occasion during his expedition against the
Galatians. (Liv. 38.13, 15.)
On the death of Antiochus III. in B. C. 187, Seleucus ascended the
throne without opposition. But the defeat of his father by the Romans, and the ignominious
peace which followed it, had greatly diminished the power of the Syrian monarchy, and the
reign of Seleucus was, in consequence, feeble and inglorious, and was marked by no striking
events. In B. C. 185, we find him sending an embassy to the
Achaeans, to renew the friendship and alliance previously existing between them and Antiochus
(Plb. 23.4, 9; Diod. xxix. Exc. Legat.
p. 622); and shortly afterwards (probably in B. C. 181) assembling a
considerable army, to assist Pharnaces, king of Pontus, against Eumenes; but he became alarmed
lest his passing Mount Taurus for this purpose should be construed by the Romans into an act
of hostility; and, in consequence, abandoned the design and dismissed his forces (Diod. Exc.
Vales. p. 576). Yet he did not hesitate to conclude a treaty of alliance with Perseus, whose
unfriendly disposition towards the Romans could no longer be a secret, and even to give him
his own daughter, Laodice, in marriage, probably in B. C. 178 (Plb. 26.7; Liv. 42.12; Inscr. Del. apud Marm. Arundel. No. 41). But he was still studious to conciliate the favour
of the Roman senate, and not long before his death sent his son Demetrius to Rome, to replace
his brother Antiochus as a hostage for his fidelity (App. Syr. 45 ;Plb. 31.12). With Egypt lie appears for the most part to have
maintained friendly relations; but Ptolemy Epiphanes is said to have been preparing for the
invasion of Coele-Syria, when his plans were frustrated by his own death (Hieronym. ad Daniel. 11.20). Towards the Jews the conduct of Seleucus seems to have
been, for the most part at least, liberal and favourable : concerning his alleged attempt to
plunder the treasury of Jerusalem see HELIODORUS.
After a tranquil and inactive reign of twelve years, Seleucus was assassinated, in B. C. 175, by one of his own ministers, named Heliodorus, who had
conceived the design of possessing himself of the sovereign power. The statement of Eusebius
that he was sixty years old, is clearly erroneous, as his elder brother Antiochus was not born
till B. C. 221. He left two children : Demetrius, who subsequently
ascended the throne; and Laodice, married, as already mentioned, to Perseus, king of
Macedonia. The name of his wife is unknown; but Froelich supposes him to have married his
sister Laodice, the widow of his brother Antiochus. (Appian, Syr. 45, 66
; Euseb. Arm. pp. 165, 166; Froelich, Ann. Syr. p. 42 ; Clinton,
F. H. vol. iii. p. 317.)