Claudius Ptolemy (90-168 AD), was a Greek-Roman citizen of Egypt (Claudius is a Roman name and Ptolemaeus is a Greek name). He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. Ptolemy was the author of several scientific treatises. His astronomical treatise, the Almagest, is the only surviving comprehensive ancient treatise on astronomy. Ptolemy's other main work is his Geographia, a compilation of what was known about the world's geography in the Roman Empire during his time. Euclid (meaning, good glory, 300 BC) was a Greek mathematician, often referred to as the "Father of Geometry". Little is known about his life. The date and place of Euclid's birth and the date and circumstances of his death are unknown. Euclid's work was translated into many different languages and it dominated mathematics for over 2000 years. The Elements of Geometry were the first mathematics books to be printed. Some errors were found in Euclid's work by the 19th century. However, most of his findings remain valid. Euclid also wrote works on perspective, conic sections, spherical geometry, number theory and rigor.