What action paved the way for the great expansion on the Aztec empire?

The great expansion of the Aztec Empire was largely facilitated by the establishment of a strong military and strategic alliances with neighboring city-states. The Aztecs, particularly under Emperor Itzcali, utilized their military prowess to conquer and absorb surrounding territories, which increased their resources and influence. Additionally, the political strategy of forming alliances through marriage and diplomacy helped to secure their dominance in the region. This combination of military strength and diplomatic maneuvering significantly contributed to the empire's rapid expansion.