The dynasty was a complex, war-like society occupied by city-states. Each city-state had its own rulers, but they were tied to the dynasty by loyalty or kinship, creating political unity. Historians know more about Shang society from written records and documents found in the capital, Anyang. Shang society was divided into a class system. At the top of the system were the king and his noble warriors, followed by the artisans, then the peasants, and at the bottom were the slaves and prisoners of war. The Shang Dynasty centered its religion on ancestor worship, a belief system based on the spirits of dead ancestors helping living relatives. This religion involved sacrifices of both animals and slaves to gain divine favor. In the 12th century, Shang leaders became oppressive and corrupt. Shang society was dominated by