The cities were built from the rubble of Old Ghis, an ancient rival of Valyria that was crushed by Valyria thousands of years before the series' events. The economies of the cities are largely based on slave labor and the slave trade. Treatment of slaves is often harsh, while citizens live in relative luxury. Professional soldiers of all three cities wear outlandish costumes and hairstyles that limit their usefulness in battle. The cities' militaries are highly dependent on additional slave and mercenary armies for the actual fighting.