Claudius Ptolemaeus, known in English as Ptolemy, was an astronomer who lived in Roman Egypt and was the author of several scientific treatises, three of which would be of continuing importance to later Islamic and European science. The first is the astronomical treatise is now known as the Almagest. Ptolemy's model was geocentric and assigned the following order to the planetary spheres around the Earth, beginning with the innermost: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Sphere of fixed stars. In Ptolemy, two players compete for control over the Ptolemaic spheres in a series of trick-taking rounds. The player who ends with more cards of a given suit gets the points corresponding to that sphere: 1 point for controlling the Moon sphere, 2 for the Mercury sphere, and so on up to 8 points for the Sphere of fixed stars. The player with most total points wins the game.