Gerard Mercator's edition of Ptolemy's 'Geography' is highly acclaimed, he spent much of his life studying the work and even engraved the plates himself. The 'Geographia' is the earliest surviving geographical treatise. Much of Mercator's efforts were spent projecting Ptolemy's geography onto the projection which bears his name. Mercator is one of the worlds greatest cartographers and the 'Claudii Ptolemaei Tabulae Geographicae Orbis Terrarum' was first published in 1578. This map is centred on Armenia and shows the Black Sea and Caspian Sea to the west and east respectively. It is in the third state with the addition of a latitude and longitude grid illustrating the projection. Koeman Me 5; Nordenskiold 234; Phillips, P.L. (Atlases) 384; Shirley BL T.Ptol-11a & 11k; Van der Krogt, P. (Atlantes) 1:501.