In Ancient Athens, about 30% of the population were slaves. The system in Athens encouraged slaves to save up to purchase their freedom, and records survive of slaves operating businesses by themselves, making only a fixed tax-payment to their masters. Athens also had a law forbidding the striking of slaves—if a person struck an apparent slave in Athens, that person might find himself hitting a fellow-citizen, because many citizens dressed no better. It startled other Greeks that Athenians tolerated back-chat from slaves (Old Oligarch, Constitution of the Athenians). Pausanias (writing nearly seven centuries after the event) states that Athenian slaves fought together with Athenian freemen in the Battle of Marathon, and the monuments memorialize them. Spartan serfs, Helots, could win freedom through bravery in battle. Plutarch mentions that during the Battle of Salamis Athenians did their best to save their "women, children and slaves".