Supervised by Spanish-born Pope Alexander VI, the Treaty of Tordesillas in 1494 divided the world in half?nto Spanish and Portuguese territories. However, following Portugal??? discovery of the Spice Islands of the Moluccas in 1512, Spain contested the line of demarcation. The issue was never fully settled, but the Treaty of Zaragoza in 1529 attempted to resolve the matter by setting the ???ntemeridian??as 17 degrees to the east of the Moluccas, thus preventing the Spanish from claiming the Spice Islands.

This 1522 map favors the Spanish claim, with the antemeridian cutting through Siam, Malacca and Sumatra, hundreds of miles west of the Moluccas.