Mercator had been working on his own world atlas of "modern" maps when he decided to pay one last tribute to the great Ptolemy and his cartography. He suspended work on his own atlas and produced an atlas of "old" maps - a '100th anniversary' edition of
This was Mercator's first published atlas as his "modern" maps atlas didn't appear
until 1585 -1595. The time and effort Mercator put into this revision was also part of his grand scheme to describe the whole ancient and modern world both geographically and historically.
These maps, engraved on copper by Mercator himself are, without a doubt, the finest ever produced for any edition of Ptolemy's work. Their quality was so fine that seven further editions were published from them over the next 150 years.