Euthydemus I

Euthydemus I, a Magnesian Greek, overthrew and killed Diodotus II, seizing the throne of the Greco-Bactrian Kingdom. This began the Euthydemid dynasty.

Euthydemus I was besieged in Bactra by the Seleucid king Antiochus III for two years. The siege ended with a negotiated peace that recognized Euthydemus's rule.

Euthydemus I negotiated a peace treaty with Antiochus III, recognizing Seleucid suzerainty in name but securing Greco-Bactrian independence. The treaty included a marriage alliance between the two dynasties.

Euthydemus I expanded the Greco-Bactrian Kingdom eastward into Sogdiana and possibly Ferghana. This extended Hellenistic influence deeper into Central Asia.