Orellana, << `oh` ray YAH nah, >> Francisco de (1511?-1546), a Spanish explorer, headed the first group of Europeans to navigate the entire length of the Amazon River in South America. In March 1541, he joined a Spanish expedition traveling eastward from Quito in what is now Ecuador. The expedition was led by Gonzalo Pizarro, a half brother of the Spanish explorer and conqueror Francisco Pizarro. The Spaniards soon began to starve and become sick. In December 1541, Orellana and about 55 other men set out by boat on a tributary of the Amazon River in search of food, but they never returned. Instead, they sailed to the Atlantic Ocean, which they reached in August 1542. Some historians consider Orellana a traitor for abandoning Pizarro. In 1544, Orellana was named governor of the territory he had explored. See Amazon River (History) .