The Battle of the Arius was an engagement that was fought in 208 BC between the Seleucid Empire and the Greco-Bactrian Kingdom. The Seleucids were led by Antiochus III the Great, who launched an invasion of Bactria to recover his ancestor's past dominions. He would go on to be victorious in this battle, and would later go on to besiege the Bactrians at their capital of Bactra for three years.

Demetrius I Anicetus was a Greco-Bactrian and later Indo-Greek king, who ruled areas from Bactria to ancient northwestern India. He was the son of Euthydemus I and succeeded him around 200 BC, after which he conquered extensive areas in what is now southern Afghanistan, Iran and Pakistan and India.