The internal structure of Maya governing elites has been much debated over the last decade. In the perspective of that debate, I propose a model of political organization at Copán at the end of the Late Classic (A. D. 750-800) based on a reinterpretation of two monuments that depict members of the governing elite, each one wearing a pectoral. The analysis of the pectorals leads to the identification of two functional groups, priests and warriors. Sovereignty incorporates both functions and is embodied in a diarchy where a coruler is adjoined to the ruler. Rulers and corulers come from the two opposing groups who, with each succession to power, exchange these roles. The executive branch, which comprises the ruler and his coruler, four ministers and four war captains, is counterbalanced by a council of nine lords. Furthermore, there are some indications that each functional group was a corporate descent group that had its own territory in the valley and its own traditions. The relations between the two groups conditioned the history of the royal dynasty, from its foundation in A. D. 426 until its collapse in A. D. 822.