Bactria was an ancient Iranian civilization in Central Asia, located in the area south of the Oxus River (modern Amu Darya) and north of the Hindu Kush mountains, within modern-day Afghanistan, Tajikistan and Uzbekistan.  Bactria was strategically located south of Sogdia and west of the Pamir Mountains. These mountain ranges acted as "walls" protecting Bactria from three sides, with the Pamir mountains to the north and the Hindu Kush to the south forming a junction, and the Karakoram range towards the east.
 
After the death of Alexander The Great, Bactria fell to his general, Seleucus I.[citation needed] The Seleucids lost the region to the satrap Diodotus I, when he declared independence; thus marking the beginning of the Greco-Bactrian and Indo-Greek Kingdoms.