The great city atop the hill reigned for at least 1,200 years, between 500 B.C. and A.D. 750, as the capital of the Zapotecs and the dominant force between Teotihuacán in the Valley of Mexico and the Maya kingdoms of the southeast. Archaeologists have organized the Valley of Oaxaca’s history from 500 B.C. to the conquest into five periods, known as Monte Albán I–V. Over those centuries, the hilltop city was repeatedly reconstructed with new walls, plazas, and staircases, which, like layers of an onion, now overlie earlier construction.

Remains from Monte Albán Period I (500 B.C.– A.D. 1) reveal an already advanced culture, with gods, permanent temples, a priesthood, a written language, numerals, and a calendar. Sharply contrasting house styles indicate a differentiated, multilayered society. Monte Albán I ruins abound in graceful polychrome ceramics of uniquely Zapotec style.

Concurrent Olmec influences have also been found, notably in the buildings known as the Danzantes (Dancers), decorated with unique bas-reliefs similar to those unearthed along the Veracruz and Tabasco coasts.

Monte Albán–II people (A.D. 1–300), by contrast, came under heavy influence from Chiapas and Guatemala in the south. They built strange, ship-shaped buildings, such as Monte Albán’s mysterious Building J, and left unique remains of their religion, such as the striking jade bat-god now on display in the Anthropology Museum in Mexico City.

Monte Albán reached its apex during the classical Period III (A.D. 300–800), attaining a population of perhaps 40,000 in an urban zone of about three square miles (eight sq. km), which spread along hilltops (including the El Gallo and Atzompa archaeological sites) west of the present city of Oaxaca.

Vigorous Period III leaders rebuilt the main hilltop complex as we see it today. Heavily influenced by the grand style of the Teotihuacán structures in the Valley of Mexico, the buildings were finished with handsome sloping staircases, corniced walls, monumental carvings, ball courts, and hieroglyph-inscribed stelae depicting gods, kings, and heroic scenes of battle.

By A.D. 750, few foreign influences were continuing to enrich Monte Albán’s uniquely Zapotec pottery styles. Quality declined until they seemed like mere factory copies. Concurrently, the Zapotec pantheon expanded to a horde of gods, as if mere numbers could protect the increasingly isolated Valley of Oaxaca from the outside world.

In A.D. 800, Monte Albán, mysteriously cut off from the rest of Mesoamerica, was declining in population and power. By A.D. 1000, the city was virtually abandoned. The reasons—whether drought, disease, or revolt—and the consequent loss of the necessarily imported water, wood, salt, and food supplies remain an enigma.

During Periods IV and V, Mixtec peoples from the north invaded the Valley of Oaxaca. They warred with valley Zapotecs and, despite their relatively small numbers, became a ruling class in a number of valley city-states. The blend of Mixtec and Zapotec art and architecture sometimes led to new forms, especially visible at the west valley sites of Yagul and Mitla.

Monte Albán, meanwhile, although abandoned, was not forgotten. It became both a refuge and a venerated burial place. In times of siege, local people retreated within the walls of a fortress built around Monte Albán’s South Platform. At other times, Mixtec nobles opened tombs and reused them as burial vaults right up until the eve of the conquest.