The stamps were issued in 1959 by Chile to commemorate the Treaty of Tordesillas.
     The Treaty resolved the rival claims of Spain and Portugal to newly discovered territories. Originally, Spain claimed all lands west of a line of demarcation 100 leagues west of Cape Verde, while Portugal received the lands to the east of this line. John II of Portugal negotiated a treaty with Spain moving the line 270 leagues further west to 46° West. As a result Portugal succeeded in laying claim to Brazil, its only colony in the new world.
     A slogan at the bottom of the stamp asserts that Spain has an old claim to Antarctica based on the Treaty.

     Christiaan Sgrooten (Sgrothenum, Schrotenus) (ca. 1532-1608) was Geographer Royal to Philip II, of Spain. {Philip also held the Low Countries as a gift from his father, Charles V.) Sgrooten made surveys and maps of the Netherlands, and contributed to the atlases of Ortelius. He also edited two manuscript atlases in 1575 and 1592. This map is dated 1588. The legend, Meridianus Partitionis inter Castellanos et Portugallenses, identifies the curved meridian of the Treaty.

     In 1529 the Treaty of Zaragoza extended the dividing line through both poles along the meridian of 162.5° E, and encompassed the world.

     The stamp issued by Spain to commemorate the Treaty of Tordesillas incorporates the date in its design.