Claudius Ptolemy (c.100 – c.170 AD)

Claudius Ptolemaeus was a Greek astronomer, mathematician, and geographer who lived in Alexandria during the 2nd century. Much of medieval astronomy and geography were built on his ideas. He was the first to use longitudinal and latitudinal coordinates. This idea of a global coordinates system was highly influential, and we use a similar system today.

Ptolemy wrote several scientific treatises. The first is the astronomical treatise now known as the Almagest, and the second is the Geography, which is a thorough discussion of the geographic knowledge of the Greco-Roman world. The third is the Apotelesmatika, an astrological treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day.

The Geographia is a compilation of geographical coordinates of the part of the world known to the Roman Empire during his time. However, the maps in surviving manuscripts of Ptolemy's Geography only date from about 1300, after Maximus Planudes rediscovered the text. It seems likely that the topographical tables are cumulative texts—texts that were altered and added to as new knowledge became available in the centuries after Ptolemy.

The earliest printed edition with engraved maps was produced in Bologna in 1477, followed quickly by a Roman edition in 1478. An edition printed at Ulm in 1482, including woodcut maps, was the first one published north of the Alps.