Centuries before Europeans arrived in the Western hemisphere, cultures that generally satisﬁed the criteria used to deﬁne civilizations had developed, primarily in the regions now known as Mexico, Guatemala, and Peru. It is impossible to know how these civilizations and other indigenous cultures would have evolved, if they had not been conquered and colonized, but studies of the Mayan cities of Copa´ n, Palenque, Chitche´n Itza´ , and Uxmal, the Aztec city of Tenochtitla´ n, the Inca cities of Cuzco and Machu Picchu, and others, reﬂect the evolution of com- plex social organizations and governments, confederations and empires, art and architecture, writing and record keeping, mathematics, astron- omy, and complex calendrical calculations. The written languages of pre-Columbian American civilizations involved hieroglyphic-like glyphs that were pictographic, ideographic, or phonetic in nature. Records were inscribed on stone monuments or recorded on paper or animal hides. Unfortunately, almost all pre-Columbian codices (manuscripts) were destroyed by the Spanish conquerors. Europeans generally deni- grated New World cultures, even the Aztec, Maya, and Inca, because they did not use iron, the plow, the arch, or an alphabet.
Their rulers might have amassed great empires and wealth, but Europeans considered native religions and governments primitive, savage, and barbaric. In the Americas, the transition from nomadic hunting and gather- ing to a sedentary lifestyle probably began in coastal Peru and the Basin of Mexico about 6000 B.C.E. The valleys of Central America and the northwest portion of South America provided the appropriate con- ditions for agricultural production, rapid population growth, diversiﬁ- cation of trade and industry, the establishment of towns and cities, and the emergence of privileged classes of priests, rulers, nobles, and warriors. Mesoamerica was the site of the rise and fall of several remarkable civilizations, including the Olmec, Zapotec, Toltec, Mixtec, Aztec, and Maya. Members of these groups cultivated a variety of important food crops, as well as tobacco and rubber, and produced drugs, poisons, fermented drinks, dyes, cloth, and ceramics. Scientists thought that corn was domesticated much later than other major cereals, such as wheat and rice, but there is evidence of the cultivation of maize in Mexico more than seven thousand years ago. In some re- gions, the basic diet of corn, beans, potatoes, manioc, yucca, tomatoes, and chilies, was supplemented with turkey, duck, ﬁsh, shellﬁsh, and even dogs and guinea pigs. Studies of the skeletal remains of people who lived in the Western Hemisphere over the last seven thousand years suggest that the general health of Native Americans had been deteriorating for centuries before 1492, but many uncertainties remain.
Thousands of skeletons from many sites in North and South America have been analyzed for evi- dence of infections, malnutrition, degenerative joint disease, dental health, stature, anemia, arrested bone development, and trauma from injuries. Declining health indicators seem to be associated with the rise of agriculture and urban cultures in South and Central America. Arche- ological evidence also suggests several periods of population growth and decline before European contact. So attributing the total collapse of New World empires to the Conquest might be excessively Eurocentric. On the other hand, the impact of European diseases and military con- quest was so profound and sudden that autochthonous patterns of pos- sible development were abruptly transformed or terminated. Europeans quickly recognized and exploited divisions and hostili- ties among native peoples who had been harshly treated by warring empires. Internal strife and tribal revolts, as well as European invaders, contributed to the fall of the Aztec and Inca empires. Contact events involving the Aztecs, Mayas, and Incas were especially dramatic, pri- marily because Mexico and Peru had the highest population densities and the most extensive trade and transport networks in the Americas. Such factors provide ideal conditions for the spread of epidemic dis- eases. Narratives of the fall of Aztec, Maya, and Inca empires suggest that Europe’s most devastating offensive weapons may have been highly contagious eruptive fevers, such as smallpox and measles, and the panic and fear that accompany exceptionally virulent epidemic diseases. Malnutrition, famine, and the breakdown of long-standing social networks would have intensiﬁed the impact of infectious diseases.