States are notoriously difficult to define. Archaeologists usually describe them as complex, centralized institutions with administrative and social hierarchies that regulate access to resources and monopolize legitimate force within substantial territories. Some features typically associated with ancient states are settlement hierarchies of four tiers, social stratification that divides the ruling elite from the nonelite, and a recognizable structure, or “palace,” which serves as a base of operations for the ruling households. In the Aegean, states did not form until the beginning of the Middle Bronze Age at the earliest. This article defines three general periods of state formation: the Protopalatial (“Old Palace”) states of Minoan Crete, Neopalatial (“New Palace”) states of Minoan Crete, and Mycenaean states of the Greek mainland and Crete (at Knossos and Khania only).