Pedro Sarmiento de Gamboa was "possibly the most talented and versatile Spanish navigator of the sixteenth century." In 1569 Viceroy Don Francisco de Toledo sent him to catch Sir Francis Drake, and to explore the Strait of Magellan and the coast of Chile for places to establish garrisons to prevent future incursions by the English and others. He established many military colonies in the strait to fortify it. He was captured on August 11, 1585 and taken to England. At the end of 1589 he was set free and returned to Spain. The map on the stamp was drawn by de Gamboa in 1582.

     The stamps below commemorate the expedition of Juan Fernández Ladrillero in 1557. Don García Hurtado de Mendoza, the Governor General of Chile appointed Ladrillero “to discover, explore and take formal possession of all the country from Valdivia south, and through the Strait of Magellan.” He sailed from Concepción, Chile November 17, 1557 and entered the Strait from the west near the end of July, 1558. He arrived at Cabo Virgenes early in August and immediately returned through the Strait. He probably did not get out until early March 1559. The map on the stamps is based on de Gamboa's map