Claudius Ptolemy was a Greek scholar who lived in around 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 late in the fifth century. There was some, but not much, knowledge of it in the eastern Empire. When a text, illustrated with maps, was brought to Rome shortly after 1400 and was translated into Latin, it caused a sensation. It paved the way for an entirely new, scientific, method of mapping and the text was much copied. This map comes from a copy of the Geographia that was created in northern Italy in about 1480. It looks very different from the form of the British Isles to be found on medieval world maps, on sea charts and on home-grown maps. The strange sharp rightward turn of Scotland is to be found on all Ptolemaic maps but was to disappear from the 'revised' or 'modern' Ptolemaic maps that were soon to appear. This map has, however, already been 'revised' in one significant way: it is drawn on a projection first thought up by Donus Nicolaus Germanus, a German monk who worked in Italy in the late 1400s. Unusually the seas are shown in yellow instead of blue.