ABSTRACT
The Classic Horizon (the first nine centuries AD) in Mesoamerica is characterised by the first phase of macro-regional integration and the popularisation of a common tradition whose precedent is found in the Middle Formative Period. Such a common tradition includes the appearance of similar architectural forms, the establishment of vast exchange networks (of obsidian, jadeite, serpentine, cinnabar, feathers, hides, and other foreign raw materials), specialised crafts, the preeminence of temple institutions in economic and ritual control in Central Mexico, the sharing of the 260-day ritual calendar and the 365-day solar calendar, common religious thoughts dominated by the Rain-Thunder-Lightning God, and the spreading of writing systems.
