Why did Montezuma II go to war with surrounding city-states

Montezuma II was the last ruler of the Aztecs in the years between 1502 and 1520, when the Spaniards conquered the empire.

During the reign of Montezuma, the Aztec Empire reached its peak of geographical size. Montezuma invaded its neighboring nations and expanded its empire all the way south to Soconusco (a territory that now borders Mexico and Guatemala). During this war, the Zapoteca and Tlapaneka nations were incorporated into the Aztec Empire, always with the aim of obtaining greater benefits through the payment of taxes and tributes by the conquered territories, but also with the aim of obtaining new prisoners to offer as sacrifice to their gods.

these conditions long with a short growing season made farming difficult.

explanation:

the north has a climate of warm summers and snowy cold winters. the terrain is rocky, hilly, and not good for farming.

answer; i believe the correct answer is (the willamete valley);