 While this interpretation cannot be ruled out, it is probably an oversimplification of the Aztec religion.
The exact significance and attributes of Quetzalcoatl varied somewhat between civilizations and through history. Quetzalcoatl was often considered the god of the morning star, and his twin brother Xolotl was the evening star (Venus). As the morning star he was known by the title Tlahuizcalpantecuhtli, meaning "lord of the star of the dawn." He was known as the inventor of books and the calendar, the giver of maize (corn) to mankind, and sometimes as a symbol of death and resurrection. Quetzalcoatl was also the patron of the priests and the title of the Aztec high priest.
Most Mesoamerican beliefs included cycles of suns. Usually, our current time was considered the fifth sun, the previous four having been destroyed by flood, fire and the like. Quetzalcoatl allegedly went to Mictlan, the underworld, and created fifth-world mankind from the bones of the previous races (with the help of Chihuacoatl), using his own blood, from a wound in his penis, to imbue the bones with new life.
His birth, along with his twin Xolotl, was unusual; it was a virgin birth, to the goddess Coatlicue. Alternatively, he was a son of Xochiquetzal and Mixcoatl.
One Aztec story claims that Quetzalcoatl was seduced by Tezcatlipoca into becoming drunk and sleeping with a celibate priestess, and then burned himself to death out of remorse. His heart became the morning star.
It has been widely believed that the Aztec Emperor Moctezuma II initially believed the landing of Hernan Cortes in 1519 to be Quetzalcoatl's return. This has been questioned by some ethnohistorians, like Matthew Restall, who argues that the Quetzalcoatl-Cortes connection is not found in any document that was created independently of post-Conquest Spanish influence, and that there is little proof of a pre-Hispanic belief in Quetzalcoatl's return. Most documents expounding this theory are of entirely Spanish origin, such as Cortes' letters to Charles V of Spain, in which Cortes goes to great pains to present the naive gullibility of the Aztecs in general as a great aid in his conquest of Mexico.
Much of the idea of Cortes being seen as a deity can be traced back to the Florentine Codex written down some 50 years after the conquest. In the codex's description of the first meeting between Moctezuma and Cortes, the Aztec ruler is described as giving a prepared speech in classical oratorial Nahuatl, a speech which, as described verbatim in the codex (written by Sahagun's, Tlatelolcan informants), included such prostrate declarations of divine or near-divine admiration.
Subtleties in, and an imperfect scholarly understanding of, high Nahuatl rhetorical style make the exact intent of these comments tricky to ascertain, but Restall argues that Moctezuma politely offering his throne to Cortes (if indeed he did ever give the speech as reported) may well have been meant as the exact opposite of what it was taken to mean: politeness in Aztec culture was a way to assert dominance and show superiority. This speech, which has been widely referred to, has been a factor in the widespread belief that Moctezuma was addressing Cortes as the returning god Quetzalcoatl.
Other parties have also propagated the idea that the Native Americans believed the conquistadors to be gods: most notably the historians of the Franciscan order such as Fray Geronimo de Mendieta. Some Franciscans at this time held millennarian beliefs and the natives taking the Spanish conquerors for gods was an idea that went well with this theology. Bernardino de Sahagun, who compiled the Florentine Codex, was also a Franciscan.
Some scholarship still maintains the view that the Aztec Empire's fall may be attributed in part to the belief in Cortes as the returning Quetzalcoatl. However, a number of Mesoamericanist scholars (such as Matthew Restall (2003), James Lockhart (1994), Susan D. Gillespie (1989), Camilla Townsend (2003a, 2003b), Louise Burkhart, and Michael E. Smith (2001) among others) consider the "Quetzalcoatl/Cortes myt