VIZCAINO, Sebastian (1548-1627), Spanish explorer of the California coast in 1602 and 1603. With four vessels including Manila galleons [shipsSan Diego; Santo Tómas; frigate Tres Reyes; and a lancha], and two hundred men and several Carmelite friars, he went as far north as Cape Mendocino, visiting many of the places Cabrillo had in 1542. Vizcaino is known to have anchored at Santa Catalina Island. He sailed into the Santa Barbara Channel on the eve of the feast day of Saint Barbara, December 4, and bestowed upon it the name of Canal de Saint Barbara. The map from his voyage named Santa Rosa Island “San Ambrosio,” but his ships did not land there. December 7 is the day of Saint Ambrosio. December 10 they landed at San Miguel Island "in Cabrillo's Harbor", named by him San Diego, in honor of his flagship. December 28, 1602 Vizcaino wrote to the Council of the Indies: “His Majesty, I have discovered many harbors, bays and islands, as far as the port of Monterey...”
The earliest Spanish maps from the 16th century show a continuous coastline. Carmelite friar, Antonio de la Ascensíon, who accompanied Sebastian Vizcaíno on his West Coast expedition of 1602-03, drew a map depicting California as an island around 1620. It is said that Spain knew it wasn't an island, but it was politically expedient for others to think it was. They weren't going to share what they knew with everybody else. Maps showing California as an island were circulated for over a hundred years. In 1747, King Ferdinand VI of Spain issued a royal decree proclaiming, "California is not an island."
- Richman, Irving Berndine. California Under Spain and Mexico 1535-1847. Boston: Houghton Mifflin Company, 1911, p. 22