Although only his books on the Roman Civil Wars survive in their entirety, large parts of Appian's book on the Syrian War, or Syriaca, have also come down to us. This book deals with the war that the Romans and the Seleucid king Antiochus III the Great fought in 192-188, but also discusses, as an appendix, the history of the Seleucid Empire. The Syriaca is a valuable source for the history of the ancient Near East between the reign of Alexander the Great and the Roman conquest.
The translation was made by Horace White; notes by Jona Lendering.
Decline of the Seleucid Empire (cont'd)
 Pompey now put Scaurus, who had been his quaestor in the war, in charge of Syria, and the Senate afterward appointed Marcius Philippus as his successor and Lentulus Marcellinus as the successor of Philippus, both being of praetorian rank.
Much of the biennial term of each was consumed in warding off the attacks of the neighboring [Nabataean] Arabs. It was on account of these events in Syria that Rome began to appoint for Syria proconsuls, with power to levy troops and engage in war like consuls. The first of these sent out with an army was Gabinius.
As he was in readiness to begin the war,note[57 BCE.] Mithridates,note[Mithridates III.] king of the Parthians, who had been driven out of his kingdom by his brother, Orodes, persuaded Gabinius to turn his forces from the Arabs against the Parthians. At the same time Ptolemy, king of Egypt, who likewise had lost his throne, prevailed upon him by a large sum of money to turn his arms from the Parthians against Alexandria.
Gabinius overcame the Alexandrians and restored Ptolemy to power,note[55 BCE.] but was himself banished by the Senate for invading Egypt without their authority, and undertaking a war considered ill-omened by the Romans; for it was forbidden by the Sibylline books.
I think that Crassus succeeded Gabinius in the government of Syria - the same who met with a great disaster when waging war against the Parthians.note[The battle of Carrhae in 53 BCE.]
While Lucius Bibulus was in command of Syria after Crassus,note[51 BCE.] the Parthians made an incursion into that country. While the government was in charge of Saxa, the successor of Bibulus, they overran the country as far as Ionia, the Romans being then occupied by the civil wars.note[In 40 BCE. In 44, Caesar had been assassinated. His relative Octavian and his former officers Lepidus and Mark Antony (the Second Triumvirate) defeated the killers near Philippi. During this civil war, the east was in great turmoil.] I shall deal with these events more particularly in my Parthian history.
The career of Seleucus
 In this book of Syrian history I have told how the Romans came into possession of Syria, and how they brought it to its present condition. It will not be amiss to tell how the Macedonians, who ruled Syria before the Romans, acquired the same country.
After the Persians, Alexander became the sovereign of Syria as well as of all other peoples whom he found. He diednote[11 June 323 BCE.] leaving one son very small and another yet unborn.note[Alexander's official wife Roxane was pregnant; she became mother of a boy, Alexander IV. His mistress Barsine was mother of a son named Heracles.] The Macedonians, who were loyal to the race of Philip, chose Arridaeus, the brother of Alexander, as king during the minority of Alexander's sons, although he was considered to be hardly of sound mind, and they changed his name from Arridaeus to Philip. They also kept careful guard over the wife, who was pregnant.
Meanwhile Alexander's friends continued in charge of the conquered nations, divided into satrapies, which Perdiccasnote[Perdiccas was regent from 323 to 320.] parceled among them by the authority of king Philip.
Not long afterward, when the true kings died, these satraps became kings.note[Philip Arridaeus was executed in 316 by Olympias, the mother of Alexander the Great, who fought for the rights of her son's son Alexander IV (more). In the winter of 312/311, the satraps concluded a treaty and promised to give their powers to the boy king, when he was old enough. Instead, the boy was immediately killed. In 306, the first of the Diadochi, Antigonus Monophthalmus, accepted the royal title, soon followed by the other rulers.] The first satrap of Syria was Laomedon of Mitylene, who derived his authority from Perdiccas and from Antipater, who succeeded the latter as regent. To this Laomedon, Ptolemy, the satrap of Egypt, came with a fleet and offered him a large sum of money if he would hand over Syria to him, because it was well situated for defending Egypt and for attacking Cyprus. When Laomedon refused Ptolemy seized him. Laomedon bribed his guards and escaped to Alcetas in Caria. Thus Ptolemy ruled Syria for a while, left a garrison there, and returned to Egypt.note[In 319-318.]
 Antigonus was satrap of Phrygia, Lycia, and Pamphylia. Having been left as overseer of all Asia when Antipater went to Europe,note[Successor of Perdiccas as regent.] he besieged Eumenes, the satrap of Cappadocia, who had been publicly declared an enemy of the Macedonians. The latter fled and brought Media under his power, but Antigonus afterward captured and killed him.
When he returned he was received magnificently by Seleucus, the satrap of Babylonia.note[In the spring of 315.] One day Seleucus punished one of the governors without consulting Antigonus, who was present, and the latter became angry and demanded an accounting of his money and possessions. As Seleucus was inferior to Antigonus in power he fled to Ptolemy in Egypt. Thereupon Antigonus removed Blitor, the governor of Mesopotamia, from office, because he allowed Seleucus to escape, and took upon himself the government of Babylon, Mesopotamia, and all the countries from Media to the Hellespont, Antipater having died in the meantime.
The other satraps at once became envious of his possession of so large a share of the territory; for which reason chiefly, and at the instance of Seleucus, Ptolemy, Lysimachus, the satrap of Thrace, and Cassander, the son of Antipater and leader of the Macedonians after his father's death, entered into a league with each other. They sent a joint embassy to Antigonus and demanded that he should share with them and with the other Macedonians who had lost their satrapies, his newly acquired lands and money. Antigonus treated their demand with scorn,note[The ultimatum was delivered in the winter of 315/314; the Third Diadoch War started in the spring.] and they jointly made war against him. Antigonus prepared to meet them. He drove out all of Ptolemy's garrisons in Syria and stripped him of all the possessions that he still retained in Phoenicia and Coele-Syria.
 Then he marched beyond the Cilician Gate, leaving his son Demetrius, who was about twenty-two years of age, at Gaza with an army to meet Ptolemy, who was coming from Egypt, but the latter defeated the young man badly in a battle near Gaza and compelled him to fly to his father. Ptolemy immediately sent Seleucus to Babylon to resume the government and gave him 1000 foot-soldiers and 300 horse for the purpose. With this small force Seleucus took Babylon, the inhabitants receiving him with enthusiasm, and within a short time he augmented his power greatly.note[In the second half of May 311. As we will see in a moment, Seleucus immediately took Media from its pro-Antigonus satrap Nicanor, and added Elam in 310.]
Nevertheless Antigonus warded off the attack of Ptolemy and gained a splendid naval victory over him near Cyprus, in which his son Demetrius was the commander.note[The naval battle of Salamis in 306.] On account of this very notable exploit the army began to call both Antigonus and Demetrius kings, as their own kings (Arridaeus, the son of Philip and Olympias, and the two sons of Alexander) were now dead. Ptolemy's army also saluted him as king lest by inferiority of rank he should be deemed less lofty than the victors in the late battle. Thus for these men similar consequences followed contrary events. All the others followed suit, and all the satraps became kings.
 In this way Seleucus became king of Babylonia. He also acquired the kingdom of Media, slaying with his own hand in battle Nicanor whom Antigonus had left as satrap of that country.note[In the winter of 311/310, five years before Seleucus accepted the royal title. Appian's chronology is a bit confused.] He afterward waged many wars with Macedonians and barbarians. The two principal ones were with Macedonians, the second with Lysimachus, king of Thrace, the first with Antigonus at Ipsus in Phrygia, where Antigonus commanded in person and fought in person although he was above eighty years of age.
Antigonus was killed in battle,note[At Ipsus, 301 BCE.] and then all the kings who had been in league with Seleucus against him divided his territory among themselves. At this division all Syria from the Euphrates to the sea, also inland Phrygia, fell to the lot of Seleucus. Always lying in wait for the neighboring nations, strong in arms and persuasive in council, he acquired Mesopotamia, Armenia, 'Seleucid' Cappadocia, Persis, Parthia, Bactria, Arabia, Tapouria, Sogdia, Arachosia, Hyrcania, and other adjacent peoples that had been subdued by Alexander, as far as the river Indus, so that the boundaries of his empire were the most extensive in Asia after that of Alexander. The whole region from Phrygia to the Indus was subject to Seleucus. He crossed the Indus and waged war with Sandrocottus,note[Ruler of the Mauryan kingdom.] king of the Indians, who dwelt on the banks of that stream, until they came to an understanding with each other and contracted a marriage relationship. Some of these exploits were performed before the death of Antigonus and some afterward.