Important 16th century ‘upside-down’ map of the Indian Ocean

A very scarce separate-issue map of the Indian Ocean, orientated with north to the bottom of the map. It shows Arabia and the Persian Gulf (with Bahrain and Muscat) on the right, with the Maldives, Sri Lanka and India west of the Ganges, with the edge of Sumatra top left. Indications that the map is based on Portuguese sources are the three vignette caravels symbolically marking the routes to Calicut and the Moluccas, the Portuguese centres in India and the Spice Islands, and Diu, a Portuguese stronghold until 1961, is shown well out of proportion. Four superb vignettes of sea monsters decorate the sea. Gastaldi's map was first published as a woodcut in 1554 but, after a fire at the printing works destroyed all the printing blocks, a copper-engraved version was cut in 1563. After Gastaldi's death in 1565 removed the threat of copyright infringement, Bertelli had Niccolo Nelli engrave this version, even copying the strip left blank at the centre fold for binding. An indication that it was copied from the original woodblock is the omission of the vignettes above (or south of) the Equator present in Gastaldi's engraving.