In 431 bc Sparta and other city states joined forces against Athens to fight the?

In 431 BC, Sparta and its allies formed the Peloponnesian League to combat Athens, which had become a dominant power in the Delian League. This conflict marked the beginning of the Peloponnesian War, a protracted struggle fueled by political, economic, and military rivalries. The war ultimately pitted the oligarchic and militaristic Sparta against the democratic and naval-oriented Athens, leading to significant consequences for both city-states and the broader Greek world.