By the mid-sixth century BCE, Greek colonists had settled in which of the following regions?

While Sparta and Thebes were indeed rival city-states in ancient Greece, they were not the primary combatants in the Peloponnesian War. The conflict primarily involved Athens and Sparta, with Thebes playing a more significant role in later conflicts, particularly after the end of the Peloponnesian War.

Athens engaged in conflicts with Persia during the earlier Greco-Persian Wars, particularly the battles of Marathon and Salamis. However, the Peloponnesian War specifically refers to the struggle between Athens and Sparta, not Persia, which was more of an external threat rather than a direct participant in this particular conflict.

Corinth was an ally of Sparta and did participate in the Peloponnesian War, but it was not the main opposing side against Athens. The war was characterized by the rivalry between Athens and Sparta, making Corinth’s involvement secondary rather than central to the conflict.