The Mask of the Sun was device that would present its wearer with visions of the future that were the most advantageous to the wearer. It was (generally) a pair of goggles, but in most timelines, the goggles were encased in a mask of gold, designed to look like a human face. The eyes were white, until worn, then they became transparent, showing the wearer visions of what he or she most wanted to know. Its origins were unknown, but it appeared to have been first created in the distant future. The Mask, or its analog, existed in multiple timelines. In most known timelines, the Mask was first given to the Aztecs in 1325. The Mask guided the Empire to glory until 1519, when Montezuma II gave the Mask to Spanish conquistador Hernán Cortés, after mistaking Cortés for a god. The Spanish used the Mask to crush the Aztecs. Upon his return to Spain, Cortés gave the Mask to his distant relative, Francisco Pizarro, who in turn used it to conquer the Incas.
However, depending on the timeline, the above course of events could vary. In at least one timeline, both the Aztec and the Inca Empire survived, thrived, and became bitter rivals. In the 23rd Century, the Aztec and the Inca were constantly at war, moving across timelines, and time itself, each trying to obtain one or more versions of the Mask and eliminate the other from a given timeline. There was a third party to this conflict: a time-traveler named Esperanza, whose origins were shrouded in mystery, and could appear to those wearing the Mask, and offer very limited help and advice.
Mask of the Sun in "Eyewear"
One version of the Mask of the Sun came into the possession of the Moorish slave Estevánico during the closing days of the Spanish Pánfilo de Narváez expedition. This version was a simple pair of goggles Estevánico found by chance. Estevánico used the "eyewear" to lead the survivors of the expedition back to safety, which took four years. Estevánico held onto the eyewear when the group finally returned to Mexico City. While here, he was alerted by the time traveler Esperanza the Aztecs; not the Aztecs of his world, but of another one, where they had 700 years to advance and thrive.
Some months after returning to the city, Estevánico became the property of Viceroy Antonio de Mendoza. Despite this change in ownership, Estevánico retained possession of the eyewear. Mendoza sent Estevánico on Francisco Vásquez de Coronado's expedition to find the Seven Cities of Gold in 1539. The eyewear was stolen from Estevánico on this trip, and Estevánico was subsequently killed. The eyewear was found over a century later by the Tewa leader, Po'pay, who with the eyewear's help, briefly liberated his people from the Spanish.
Po'pay's revolution is the center of the story "Like the Rain" by Jane Lindskold, the story immediately following "Eyewear" in Golden Reflections. However, Lindskold depicts Po'pay acquiring a conventional Mask, and not the eyewear, in a different circumstance than in Turtledove's story. Thus, it does not appear that Lindskold and Turtledove were building on each other's continuity, and that the two stories are not part of the same timeline.
- The Mask of the Son, Fred Saberhagen, Chapter 2. In Walter Jon Williams' story, "The Fate Line", we are informed that the Mask was first sent to Ancient Egypt, only to be buried with the reigning pharaoh upon his death in virtually every timeline. Only in one timeline was the Mask recovered from the tomb.
- Ibid. Ch. 4.
- Ibid. Ch. 6.