Arsaces Tiridates soon added Hyrcania to his realm and raised a great host to maintain himself against Seleucus, but still more against a nearer enemy, Diodotus of Bactria. On the death of the latter, the common interests of Parthians and Bactrians as against the Seleucids brought about an alliance between Arsaces Tiridates and Diodotus II. With much ado, Seleucus had got the better of his foreign and intestine foes and kept his kingdom together; and in 238 B.C., or a little later, having made peace with Egypt and silenced his brother, he marched from Babylon into the upper satrapies. Tiridates at first retired and took shelter with the nomadic Apasiacæ, but he advanced again and gained a victory, which the Parthians continued to commemorate as the birthday of their independence. Seleucus was unable to avenge his defeat, being presently called back by the rebellion stirred up by his aunt Stratonice at Antioch. This gave the great Hellenic kingdom in Bactria and the small native state in Parthia time to consolidate themselves. Tiridates used the respite to strengthen his army, to fortify town and castles, and to found the city of Dara or Dareium in the smiling landscape of Abévard. Tiridates, who on his coins appears first merely as Arsaces, then as King Arsaces, and finally as “great king,” reigned thirty-seven years, dying in 211 or 210 B.C. His nation ever held his memory in almost divine honour. [Illustration: A PARTHIAN KING] Seleucus III Soter (226-223 B.C.) died early, and was followed by Antiochus (III) Magnus (223-137 B.C.), who in his brother’s life-time had ruled from Babylon over the upper satrapies. Molon, governor of Media, supported by his brother Alexander in Persis,[29] rose against him in 222 B.C. and assumed the diadem. The great resources of his province, which followed him devotedly, enabled Molon to take the offensive and even to occupy Seleucia, after a decisive battle with the royal general Xenœtas. Babylonia, the Erythræan district, all Susiana except the fortress of Susa, Parapotamia as far as Europus, and Mesopotamia as far as Dura were successively reduced. But the young king soon turned the fortunes of the war. Crossing the Tigris in person, he cut off Molon’s retreat. Molon was forced to accept battle near Apollonia: his left wing passed over to the enemy, and, after a crushing defeat, he and all his kinsmen and chief followers died by their own hands (220 B.C.). Antiochus now marched to Seleucia to regulate the affairs of the East. He used his victory with moderation, mitigating the severities of his minister Hermias; but he had effectually prevented the rise of a new kingdom in the most important province of Iran. [Sidenote: [206-155 B.C.]]