BEIJING, Dec. 28 (Xinhuanet) -- The ruins of an 800-year-old Aztec pyramid discovered in the central Tlatelolco area had updated the foundation time of the Mexico City at least by a century, media reported Friday.

    The ancient city, once a major religious and political center for the Aztecs, was thought to be founded in 1325 after the discovery of another pyramid at the site 15 years ago.

    "We have found the stairs of this, much older pyramid. The (Aztec) timeline is going to need to be revised," archeologist Patricia Ledesma said.

    The newly found pyramid is believed to have been built in 1100 or 1200. The ruin is about 36 feet (11 meters) high, and more studies are still needed for prove the pyramid's size and age.

    "What we hope to find soon should tell us much more about the society of Tlatelolco," said Ledesma.

    Mexico City is littered with pre-Hispanic ruins.

    The Aztecs, a warlike and religious people who built monumental works ruled an empire stretching from the Gulf of Mexico to the Pacific Ocean and encompassing much of modern-day central Mexico.

    (Agencies)