Final answer:
Sparta was the Greek city-state that emphasized war, known for its military strength, austere society, and rivalry with Athens, particularly during the Peloponnesian War.
Step-by-step explanation:
The Greek city-state that emphasized war was Sparta. Known for its military prowess and austere way of life, Sparta was often in rivalry with the more cultured and politically innovative city-state of Athens during the Classical Age. The two city-states clashed during the Peloponnesian War, where Sparta demonstrated its military dominance by eventually forcing Athens to sue for peace.
While Athens was known for its contributions to art and the birthplace of democracy, Sparta was recognized for its because an oligarchy focused on military discipline, training, and excellence in war.