Demetrius I Soter

Demetrius I Soter (Ancient Greek: Δημήτριος Α` ὁ Σωτήρ, Dēmḗtrios ho Sōtḗr, "Demetrius the Saviour"; 185 – June 150 BC) reigned as king of the Hellenistic Seleucid Empire from November 162 to June 150 BC. Demetrius grew up in Rome as a hostage, but returned to Greek Syria and overthrew his young cousin Antiochus V Eupator and regent Lysias. Demetrius took control during a turbulent time of the Empire, and spent much of his time fighting off revolts and challenges to his power from threats such as Timarchus and Alexander Balas.

Demetrius was born around 185 BC. He was sent to Rome as a hostage at a young age during the reign of his father Seleucus IV Philopator and his mother Laodice IV. Rome taking prominent Seleucid family members hostage was one of the terms of the Treaty of Apamea that had ended the Roman-Seleucid War. His father was likely murdered by his finance minister Heliodorus in 175 BC; his uncle Antiochus IV Epiphanes overthrew Heliodorus and took the throne himself. While the throne should have gone to Demetrius, he was both too young and also still held as a hostage in Rome. Antiochus IV died around October–November 164 BC while on campaign in Babylonia and Persia. His 9-year-old son Antiochus V Eupator became king, although real power rested with Lysias, the regent Antiochus IV had left in Antioch. Demetrius, 22 years old then, requested the Roman Senate to restore the Seleucid throne to him, but was rejected, since the Romans wanted a weak Seleucid Empire and therefore preferred a boy king to a man. Two years later, Antiochus V was greatly weakened; Rome had sent an emissary to sink his ships and hamstring his elephants according to the terms of the Treaty of Apamea. Demetrius again petitioned the Senate on the grounds that his captivity would do little to inspire Antiochus V to heed Rome, but the appeal was again unsuccessful, as Rome preferred the perceived weak boy king over him. With the help of the Greek historian Polybius, Demetrius escaped from confinement and made his way to the Seleucid capital Antioch. There he successfully gained the support of the local aristocracy and took the Seleucid throne from his cousin in around November 162 BC. He immediately executed Antiochus V and Lysias.

This phase of Demetrius's life is unusually well-chronicled, as Polybius was an active participant and advisor to Demetrius, and his book The Histories survived out of antiquity rather than being a lost book.

The Romans were not enthusiastic about Demetrius's rule. They offered their indirect support and encouragement to any who would seek to divide the Seleucid Empire, and hence weaken it. Notably, this included the satrap Timarchus; the Jewish Maccabees; Ptolemaeus of Commagene; and Artaxias I of Armenia.

Demetrius instituted measure to suppress the Maccabean Revolt in Judea. According to the books of the Maccabees Demetrius sent a certain Alcimus as a new High Priest to Judea shortly after his reign started. Alcimus was able to persuade some of the Jews to return to the Seleucid fold. Demetrius also dispatched an expedition under Bacchides which broke Maccabee influence over the Judean cities. Bacchides and his forces defeated and killed the rebel leader Judas Maccabaeus at the Battle of Elasa in 160 BC, restoring Seleucid control to the province for a number of years.

Demetrius acquired his surname of Soter (Savior) from the Babylonians, when he defeated Timarchus, the rebellious satrap of Media . Timarchus, who had distinguished himself by defending Media against the emergent Parthians, seems to have treated Demetrius' accession as an excuse to declare himself an independent king and extend his realm into Babylonia. His forces were, however, not enough to stand against the new Seleucid king: Demetrius defeated and killed Timarchus in 160 BC, and dethroned Ariarathes, king of Cappadocia. The Seleucid empire was temporarily united again.

Demetrius may have married his sister Laodice V, by whom he had three sons: Demetrius II Nicator, Antiochus VII Sidetes, and Antigonus.

Demetrius' downfall may be attributed to Heracleides, a surviving brother of the defeated rebel Timarchus, who championed the cause of Alexander Balas, a boy who claimed to be a natural son of Antiochus IV Epiphanes. Heracleides convinced the Roman Senate to support the young pretender against Demetrius I. Balas's mercenary army landed and occupied Ptolemais, and started a reign proclaiming himself as king of the Seleucids in Seleucid year 160 (153–152 BC). The Seleucids now had two kings locked in civil war.