Garci Rodríguez de Montalvo (Spanish pronunciation: [ˈgarθi roˈðɾiɣeθ ðe monˈtalβo]) (or Garci Ordóñez de Montalvo) (~1450 – 1504) was a Spanish author who arranged the modern version of the chivalric romance Amadis of Gaul, written in three books in the 14th century by an unknown author. Montalvo added a fourth book of his own and also wrote a sequel, Las sergas de Esplandián (The Exploits of Esplandian) (oldest known printing, 1510), in which he tells the life and wandering of Amadis' eldest son. The saga was continued in the sixth book "Florisando" (by Ruiz Paez de Ribera, 1510), followed by "Lisuarte of Greece" (by Feliciano de Silva, 1514), "Lisuarte of Greece" (by Juan Diaz, 1525), "Amadis of Greece" (by Feliciano de Silva, 1530), etc.
In the sequel, Rodríguez described a mythical Island of California as being west of the Indies:
The novel was highly influential in motivating Hernán Cortés and other explorers in the discovery of the "island", which they believed lay along the west coast of North America. In 1539, Francisco de Ulloa, sailing under the commission of Cortés, explored the Gulf of California and the coast of Baja California peninsula, determining that it was a peninsula, not an island. Nevertheless, the cartographic misconception of California as an island persisted on many European maps well into the 18th century.