Following the shift in population of the Pueblo region, cultural changes occurred that have led to the designation Regressive Pueblo period (Pueblo IV) for the interval between 1300 and 1700 A.D. Noteworthy changes during this period include a tendency toward enlargement of villages and the creation of new styles of pottery, accompanied by some deterioration of the artistic creativity of the Classic period. Major ruins of this period that are readily accessible to the public include Puye Cliff Dwellings, Tyuonyi Pueblo in Bandelier National Monument, and Pecos Pueblo in Pecos National Monument. At the time of Coronado’s _entrada_ in 1540, there were from 60 to 70 Pueblo villages in New Mexico, most of which contained fewer than 400 inhabitants. Four or five mutually unintelligible languages were spoken, each with several dialects, making communication between Spanish and Indian extremely difficult. Language barriers contributed to an inadequate documentation of the Pueblo way of life during the early years of Spanish contact, so that we must continue to depend upon the archeological record during the first century of Spanish colonization of the area. The beginning of the Historic Pueblo period (Pueblo V) accordingly is commonly set at 1700 A.D. APACHES AND NAVAJOS Little is known concerning the origin of these two related groups, who differ markedly from the Pueblo Indians in language and cultural traits. Their closest ties are with other Athapaskan-speaking tribes in northwestern Canada, and available evidence indicates that they are comparative newcomers to the Southwest. A correlation between the abandonment of sections of the Pueblo region and pressures exerted by ancestral Apaches and Navajos has been suggested, but definite proof of this is still lacking. Raids against the eastern pueblos of the Galisteo Basin are reported to have occurred in 1525. Coronado’s expedition encountered nomadic hunters in the plains east of Pecos in 1541, observing that they followed the movements of herds of bison or buffalo on whom they were highly dependent for food and shelter, lived in portable tents of tanned buffalo hides supported by a framework of poles, and used dogs as beasts of burden. Trade contacts with the Rio Grande pueblos included exchange of hide “cloaks” for corn grown by the Pueblo Indians. Related groups in western and northwestern New Mexico are even more poorly known, as there was still less contact between them and the Spanish explorers. Evidently some agriculture was practiced as a supplement to a subsistence based largely on hunting and gathering, a pattern of livelihood reminiscent of that of the pre-Puebloan Cochise people. The succeeding years of Spanish and American colonization of New Mexico were to be highly influenced by the Apaches and Navajos, and also by another group of Plains Indians, the Comanches. The events of this period, however, are discussed in a separate article.