Seleucus (or Seleukos) of Seleucia (born c. 190 BC, fl. 150s BC), also known as Seleucus of Babylon, was a Chaldean Babylonian astronomer and philosopher from Seleucia on the Tigris (and/or Babylon) in Babylonia, Mesopotamia. Seleucus is known from the writings of Plutarch, Aetius, Strabo and Muhammad ibn Zakariya al-Razi. Strabo lists Seleucus as one of the four most influential Chaldean/Babylonian astronomers, alongside Kidenas (Kidinnu), Naburianos (Naburimannu) and Sudines. Their works were originally written in Akkadian Cuneiform and later translated into Greek. Seleucus, however, was unique among them in that he was the only one known to have supported the heliocentric theory of planetary motion.