They both had laws and also they were both the two main cities of Greece. Sparta began as a monarchy and Athens began as an Aristocratic city-state, but both changed their governing bodies around 700 BC. They also each had slaves, though they were attained differently. Each trained their boys for battle, though Spartans did so much earlier in life. They were also both involved in major ancient Greek battles, as often as not, with each other! They treated slaves equally, and they were both city-states.