it all started when the mexica people helped the Culhuacan people win a battle and were gifted the kings Daughter. She was to be married to someone from the Mexica tribe.
once the dad/king turned up for the wedding he saw the priest wearing her skin as his own. They had sacrificed the princess. The king was furious but the mexica people tried to explain that their god Huitzilopochtli had told them to do it.
They king declared a war against the Mexica people.the mexica people lost and were thrown out for the city
their god Huitziliopotchli told them to look for a sign. He said that once they find a white eagle with a snake in it's mouth while perched on a cactus, that that is where they should settle.
They were forced to leave Chapultepec and move to some marshy islands in the middle of the lake texcoco
they slowly grew their kingdom into the most feared