Pacific Ocean for the Spanish Crown, as well as all adjoining land and islands. This act gave Spain exclusive sovereignty and navigation rights over the entire west coast of North America. The commonly held belief at the time was that the west coast of North America was in modest sailing distance of Asia to the west, or the two might actually physically connect. To the north was imagined a narrow Northwest Passage, known as the Strait of Anián, which some believed reached the Pacific Ocean at 42° north latitude (the latitude of today's border between Oregon and California) and connected to the Atlantic Ocean at the Gulf of St. Lawrence. Confirmation of the land connection, and discovery of this Strait of Anián, were key elements in Spain's efforts to establish direct trade routes with China and other countries in Asia. See Early knowledge of the Pacific Northwest. The Pacific Coast of Mexico and Central America was not especially conducive to economic development during this era. The northern Mexican coast (including the Baja California Peninsula) was generally too dry for substantial agriculture or ranching that would support settlements. South of the deserts, the jungles of the Pacific Coast in Mexico and Central America, and the tropical diseases found there, were major obstacles to large-scale development. Notable exceptions were the development of important Spanish ports at Puerto de Navidad and Acapulco in today's Mexico. While Navidad faded in importance, Acapulco became the primary port of the Spanish Empire on the west coast of North America, and was used as a base for exploratory expeditions north and trade routes with the Far East. From 1533–1535, Spanish conquistador Hernán Cortés personally sponsored and financed exploratory sailing voyages north from Acapulco, in a search for legendary riches reported to be in the site of today's California. In the third of these voyages, Cortés accompanied the voyage, and likely reached the site of today's La Paz on the Baja California peninsula. In 1539, another voyage financed and sponsored by Cortés, and led by Francisco de Ulloa, embarked on an expedition in three small vessels, sailing north from Acapulco to explore the Pacific Coast, and to seek the Strait of Anián. The expedition sailed northwards along the west coast of the Mexican mainland, and reached the Gulf of California six weeks later. Ulloa named the Gulf the "Sea of Cortés" in honor of his patron. When one