The Maya is a Mesoamerican civilization, noted for the only known fully developed written language of the pre-Columbian Americas, as well as for its art, architecture, and mathematical and astronomical systems. Initially established during the Pre-Classic period (c. 2000 BC to 250 AD), according to the Mesoamerican chronology, many Maya cities reached their highest state of development during the Classic period (c. 250 to 900 AD), and continued throughout the Post-Classic period until the arrival of the Spanish.