Final answer:
The Triple Alliance was an alliance formed between the Aztecs, Texcoco, and Tlacopan. Itzcoatl reshaped Aztec history by forming the alliance and expanding the empire.
Step-by-step explanation:
The Triple Alliance was an alliance formed in 1428 between the Aztecs and two neighboring city-states, Texcoco and Tlacopan. It was also known as the Aztec Empire.
The alliance allowed the Aztecs to launch a surprise attack on the city-state of Atzcapotzalco and become the dominant regional power.
Itzcoatl, who was a ruler of the Aztecs, played a significant role in reshaping Aztec history. He helped form the Triple Alliance and initiated military campaigns to expand their control over central Mexico.
Under his rule, the Aztec Empire expanded its territory and became a powerful and influential empire in Mesoamerica.