Definition: In this task you will be given a question and a passage. You need to determine if the answer to the question is contained in the passage. If the answer can be found in the passage you should output 'True'. If the answer cannot be found in the passage you should output 'False'.
Input: Passage: 'The Aztec Empire, or the Triple Alliance (Classical Nahuatl: Ēxcān Tlahtōlōyān, (ˈjéːʃkaːn̥ t͡ɬaʔtoːˈlóːjaːn̥)), began as an alliance of three Nahua altepetl city-states: Mexico-Tenochtitlan, Texcoco, and Tlacopan. These three city-states ruled the area in and around the Valley of Mexico from 1428 until the combined forces of the Spanish conquistadores and their native allies under Hernán Cortés defeated them in 1521.'. Question: 'when did the aztec empire begin and end'.

True