SELEUCIA, in Ancient Geography, surnamed Babylonia, because situated on its confines, at the confluence of the Euphrates and the Tigris. Ptolemy places it in Mesopotamia. It is called also Seleucia ad Tigrim, being washed on the south by the Euphrates, and on the east by the Tigris. It is generally believed to have been built or enlarged by Seleucus Nicanor, master of the east after Alexander by means of which Babylon came to be deserted. It is said to have been originally called Cochæ, though others, as Arrian, distinguish it, as a village, from Seleucia; and, according to Zosimus, the ancient name of Seleucia was Zochæia. It is now called Bagdad. Long. 44. 21. E. Lat. 33. 10. N. There were many other cities of the same name, all built by Seleucus Nicanor.