Some of the living rooms in the pueblo bear evidence of Mesa Verde workmanship, and almost 95% of the pottery is of the Mesa Verde type. This gave rise to the belief that Aztec was a hybrid settlement of people of both cultures. Excavation proved that the explanation was not quite so simple. The original builders of the Pueblo and Great Kiva had Chacoan connections. They occupied the Pueblo for many years, then, taking their possessions with them, they moved away. Why they left, or where they went, we do not know. For a long time the Pueblo was abandoned, then a group of Mesa Verde people arrived and moved in. They changed and modified many of the rooms in accordance with their own customs. The rooms which they built were smaller and the masonry was of the typical Mesa Verde type, as was the pottery. After this immigration the great house was occupied for a long time. At first the people were quite prosperous, but eventually there came a period of depression and disintegration. Building techniques became progressively worse, and there was an equal deterioration in pottery making. Living quarters were no longer cleaned. Many women and children died, and, when they were buried few, if any, mortuary offerings were placed with them. The end came when the pueblo was intentionally fired and destroyed. Whether this was done by the people themselves, or by enemies who attacked them when they were no longer able to defend themselves, we do not know. In the vicinity of Kayenta, Arizona, which lies to the south of the San Juan and west of both Mesa Verde and Chaco Canyon, was a third cultural center with far-reaching influences.[3][73] Here are found both cliff houses and pueblos in the open. Two of the largest and most famous cliff dwellings are Keet Seel and Betatakin. These were among the last of the great houses of the San Juan area to be occupied. Tree-ring dates for Betatakin range between 1260 and 1277, and those for Keet Seel between 1274 and 1284. By the latter date the remainder of the northern frontier had been almost entirely deserted.