Euthydemus I was a Greco-Bactrian king in about 230 or 223 BC according to Polybius; he is thought to have originally been a satrap of Sogdiana who overturned the dynasty of Diodotus of Bactria and became a Greco-Bactrian king. Strabo, on the other hand, correlates his accession with internal Seleucid wars in 223–221 BC. His kingdom seems to have been substantial, including probably Sogdiana to the north, and Margiana and Ariana to the south or east of Bactria.
Little is known of his reign until 208 BC when he was attacked by Antiochus III the Great, whom he tried in vain to resist on the shores of the riverArius, the modern Herirud. Although he commanded 10,000 horsemen, Euthydemus initially lost a battle on the Arius and had to retreat. He then successfully resisted a three-year siege in the fortified city ofBactra, before Antiochus finally decided to recognize the new ruler, and to offer one of his daughters to Euthydemus's son Demetrius around 206 BC. As part of the peace treaty, Antiochus was given Indianwar elephants by Euthydemus. Classical accounts also relate that Euthydemus negotiated peace with Antiochus III by suggesting that he deserved credit for overthrowing the descendants of the original rebel Diodotus, and that he was protecting Central Asia from nomadic invasions thanks to his defensive efforts: The war lasted altogether three years and after the Seleucid army left, the kingdom seems to have recovered quickly from the assault. The death of Euthydemus has been roughly estimated to 200 BC or perhaps 195 BC, and the last years of his reign probably saw the beginnings of the Bactrian incursions into Northern India.
Coinage
There exist many coins of Euthydemus, portraying him as a young, middle-aged and old man. He is also featured on no less than three commemorative issues by later kings, Agathocles, Antimachus I and one anonymous series. He was succeeded by Demetrius, who went on to invade northwestern regions of South Asia. His coins were imitated by the nomadic tribes of Central Asia for decades after his death; these imitations are called "barbaric" because of their crude style.
In an inscription found in the Kuliab area of Tadjikistan, in western Greco-Bactria, and dated to 200-195 BC, a Greek by the name of Heliodotos, dedicating a fire altar to Hestia, mentions Euthydemus as the greatest of all kings, and his son Demetrius I as "Demetrios Kalinikos" "Demetrius the Glorious Conqueror":
