For 10 points, name this Hellenistic kingdom roughly covering the flat regions north of the Hindu Kush.
Coins issued by the first dynasty to rule this polity usually showed Zeus preparing to throw a thunderbolt on the reverse, while those minted by that dynasty's successor featured a nude Heracles sitting on a pile of rocks. Along with a centaur, the Sampul Tapestry depicts a warrior thought to be from this polity, whose final ruler was Heliocles. After losing the Battle of the Arius and withstanding a three-year siege of his capital, a king of this polity named Euthydemus I married the daughter of and was officially recognized by (*) Antiochus III. A southern neighbor to this kingdom was founded by one of its rulers, who was often depicted with headgear made from the scalp of an elephant. That man, Demetrius I, promoted Buddhism in his territories. This kingdom suffered from the expansion of the Yuezhi, and was founded by Diodotus, a satrap of the Seleucid Empire who seceded in the 250s BC. For 10 points, name this Hellenistic kingdom roughly covering the flat regions north of the Hindu Kush. 
Coins issued by the first dynasty to rule this polity usually showed Zeus preparing to throw a thunderbolt on the reverse, while those minted by that dynasty's successor featured a nude Heracles sitting on a pile of rocks.
Greco-Bactrian Kingdom