Many of the Sinagua in the modern Flagstaff region to the north began to leave their dry-farming area in the early 1200’s. They also seem to have migrated into the Verde Valley. Since they had depended on rainfall for their crops, it is quite possible that the drought affected their entire area, forcing them to move down from the Flagstaff area as well as from the northern and eastern parts of the valley. The occupants of the central region of the valley were able to survive because of the spring-fed streams upon which they depended for their irrigation and water supply. Such a move undoubtedly disturbed the balance of the people and the available food in the now overcrowded central area. Considerable friction must have arisen. The combination of too many people and not enough farmland may have eventually caused intervillage strife over water rights, with general population decline caused by soil exhaustion and the reduction of other resources. Montezuma Castle was built up to its present size at this time, reaching its maximum in the 1300’s. Consolidation was also in progress at Montezuma Well. Between 1300 and 1400, only 3 farm outlooks along that half of the irrigation ditch nearest the Well were occupied. In this way the area of settlement was contracted or reduced by abandonment of outlying sites. The concentration of population around the Well implies conflict of some sort; and, it was at this time that the large, definitely defensive pueblo on the rim was constructed. By 1400, or shortly thereafter, the Sinagua abandoned the Well. Shortly after 1400, in fact, Montezuma Castle and the entire Verde Valley were abandoned by the Sinagua. There is no direct evidence to supply us with the reason for this complete exodus—a combination of circumstances is the probable answer. A possible major factor causing the Sinagua to abandon the area may have been the Yavapai Indians whom the Spanish later encountered in the Verde Valley. The Yavapai could have been descendents of those Hohokam who had stayed in the valley and lived with the Sinagua between 1100 and 1400. (Like the Hohokam, the Yavapai cremated their dead, built pole-and-brush houses, and farmed small plots along the stream bottomlands.) If they were descendents of the Hohokam, the Yavapai might have been the victors in the intervillage strife that apparently occurred during the 1300’s and forced the Sinagua to leave the valley.