Claudius Ptolemy was a Greek scholar who lived in about 150 AD. Utilising the resources of the great library of Alexandria in Egypt he compiled a description of the world based on the writings of Greek astronomers, mathematicians and geographical writers of earlier centuries. The resulting book, the Geographia (also known as the Cosmographia) contained instructions on how to construct maps using projections to 'flatten' the image of the Earth and co-ordinates to place geographical features and towns. It is not known whether he actually drew any maps. The book never seems to have been well known in the western Roman empire and its text was completely lost following the Empire's fall in the late fifth century. There was some, but not much, knowledge of it in the eastern Empire. This Greek copy of Ptolemy's Geographia dates from about 1400 and the map is oriented with South at the top.