Popol nahs, or council houses, have been identified for the Late and Terminal Classic periods in the northern Maya lowlands. This chapter focuses on the earliest proposed examples, examining the characteristics and assumptions used to define them and understand their role in the evolution of Classic Maya society. Examples from Ek Balam, Kiuic, and Labna are discussed in detail in order to consider the reality of popol nahs, their function in the development of social stratification in the northern Maya lowlands, and how they may also reflect changes in social organization during the Late and Terminal Classic periods (AD 550-1000). We argue that popol nahs are a manifestation in architecture of one of the central organizing principles of northern Maya lowland society from at least the early Late Classic Period onward.