Just outside of the city of Toluca can be seen the impressive ruins of Teotenango, an ancient citadel built by a little-understood civilization. It is believed by scholars that the city of Teotenango was founded in the centuries that preceded the collapse of the mighty civilization of Teotihuacan around the year 900. The true identity of the ancient peoples who constructed the city remains something of a mystery. But several compelling theories regarding the identity of the Teotenanca have been proposed by the archeologists who have excavated the site since the…