The Classic Period (250 - 900 A.D.)
Divided into three phases:

Early Classic Phase (250-600 A.D.)

The Guatemalan highland area reached its cultural peak.  The characteristic features of the Mayan civilization were firmly established.  The corbel vault was invented, the calendar was perfected, astronomy and mathematics were developed.

Florescence Phase (600-800 A.D.)

The greatest period of sculpture, writing, and architecture in the central lowland area developed during this period.  The Guatemalan highlands were on the decline.

The Collapse (800-900 A.D.)

The central lowland cities were abandoned.  The northern Yucatan cities continued to thrive, although Mexican influences were starting to be felt.  The Puuc style of architecture reached its peak.