Tianquiztli which in translation means "Marketplace". Tianquiztli was the Aztec

Aztec

The Aztec people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the late post-classic period in Mesoamerican chronology.Aztec is the...

's name for the Pleiades

Pleiades (star cluster)

In astronomy, the Pleiades, or Seven Sisters , is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky...

. Time was measured by movements of the stars and the sun. Their calendar was based upon a fifty-two year cycle. They watched Tianquitzli (Pleiades) closely.

The crossing of the meridian by the Pleiades signaled that the cosmos did not interrupt their movement, and the world would not end then and another fifty two years were safe of the apocalypse and that demons of darkness descending to earth and devouring men. This also ensured that the sun was reborn. At the specific moment when the Pleiades crossed the meridian, the Aztec priests would start a small fire on the slashed chest of the victim. The same fire was then carried to the temple of the Sun god Huitzilopochtli

Huitzilopochtli

In Aztec mythology, Huitzilopochtli, also spelled Uitzilopochtli , was a god of war, a sun god, and the patron of the city of Tenochtitlan. He was also the national god of the Mexicas of Tenochtitlan.- Genealogy :...

, and to the homes of the Aztec people.