In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.

Context: Totonac ethnicity dominated this large region, although they themselves were dominated by the Aztec Empire. Link Information: The Aztec Empire, or the Triple Alliance (, ]), was an alliance of three Nahua city/states: , , and . These three city-states ruled the area in and around the Valley of Mexico from 1428 Answer: 1428
When was the Empire that dominated the People of Totanac ethnicity formed?