Rival of Sparta can be found in two crossword solutions: ATHENS (6 letters) and Argos (5 letters). ATHENS was the capital of ancient Greece and a major city-state in the region. It was known for its cultural and political achievements, such as the development of democracy. Argos was another major city-state in ancient Greece, located in the northeastern Peloponnese. It was known for its military strength and its rivalry with Sparta. Both ATHENS and Argos were rivals of Sparta, the dominant city-state in the region.