<Tr> <Td> Monte Alban 3 </Td> <Td> ca AD 200 - 900 </Td> </Tr> <Tr> <Td> Monte Alban 4 </Td> <Td> ca 900--1350 </Td> </Tr> <Tr> <Td> Monte Alban 5 </Td> <Td> ca 1350--1521 </Td> </Tr> <P> Zapotec civilization originated in the Central Valleys of Oaxaca in the late 6th Century BC . The three valleys were divided between three different - sized societies, separated by 80 km "no - man's - land" in the middle, today occupied by the city of Oaxaca . Archaeological evidence, such as burned temples and sacrificed captives, suggests that the three societies competed against each other . At the end of the Rosario phase (700--500 BC), the valley's largest settlement San José Mogote, and a nearby settlement in the Etla valley, lost most of their population . During the same period, a new large settlement emerged in the "no - man's - land" on top of a mountain overlooking the three valleys, that was called Monte Albán . Early Monte Albán pottery is similar to pottery from San José Mogote, which suggests that Monte Albán was populated by the people who left San José Mogote . Although there is no direct evidence in the early phases of Monte Albán's history, walls and fortifications around the site during the archaeological phase Monte Alban 2 (ca . 100 BC--200 AD) suggest that the city was constructed in response to a military threat . Archaeologists Joyce Marcus and Kent V. Flannery liken this process to what happened in ancient Greece - (synoikism): a centralization of smaller dispersed populations congregated in a central city to meet an external threat . </P>

What type of structure did the zaptec build