Ptolemy

Ptolemy (Claudius Ptolemaeus), the astronomer and geographer, lived in Egypt in the 2nd century after Christ. His works were textbooks throughout the Middle Ages. His astronomical writings, from which was gathered the Ptolemaic System, consisted of the Almagest (The Great Work), or, according to its Greek title, The Great System of Astronomy; the work which contains the Tetrabublos Syntaxis and the Karpos or Book of a Hundred Aphorisms; and a Treatise on the Phenomena of Fixed Stars. The Geographia, a work in eight books, illustrated by a map of the world and twenty-six other maps, was founded on the labours of a certain Marinus of Tyre. Ptolemy took Ferro in the Canaries as the westernmost part of the world from which to calculate his longitudes, and placed it nearly 7° too far east. Latitudes were reckoned from Rhodes.