It was a siege of the city of Bactra by the Seleucid Empire after they defeated the Greco-Bactrians at the Battle of the Arius.

The Seleucids besieged the capital of Bactria until concerning news from the west of his dominions and lack of progress against the city led the Seleucid ruler Antiochus III to negotiate a peace treaty with the Bactrian king Euthydemus and lift the siege.

The Greco-Bactrians had recently been defeated at the Battle of the Arius by Antiochus III.

Impressed at Demetrius' behaviour and bearing which was seen as worthy of that of a member of the royalty, Antiochus offered him one of his daughters and agreed to a peace treaty.

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