The history of Chichen Itza as with many aspects of Mayan history is obscure: Written records are scarce.
In the historical records which is exist, dates that were several years apart were often given the same name, due to the organization of the old Mayan calendar.
Roughly all sources agree that from approximately 550 AD to 800 AD, Chichen Itza existed mainly as a ceremonial center for the Maya civilization.
The area was then largely abandoned for about a hundred years (no one knows reason ), to be resettled around 900 AD again. Shortly before 1000 AD, it was invaded by a people from the north ( the Toltecs ).
The Toltecs had settled near modern-day Mexico City at Tula, around 900 AD under the rule of a king Topiltzin. Topiltzin also took the name of “Feathered Serpent,” or Quetzalcoatl, the name of an Aztec god.
A rival warrior faction forced Topiltzin Quetzalcoatl and also his followers out of Tula around 987 AD.
Mayan historical sources mention that a man who called himself Kukulkan arrived in Chichen Itza from the west (Kukul means “feathered” and kan means “serpent”) in the period that ended in 987 AD. A strong case has been made that Kukulkan and Topiltzin Quetzalcoatl were most likely the same person, and that he brought the Toltec practices and beliefs to Chichen Itza, including the practice of human sacrifice.
The Toltecs were somewhat open to new ideas, however, at Chichen Itza incorporating some beliefs held by the Maya already.
• The city is divided into two different principal areas: Chichen Viejo (Old Chichen) and Chichen Nuevo (New Chichen).