Modern and Ancient Definitions. Old age in American society, especially the modern view of when the period starts, has shifted dramatically in the last century. At the beginning of the twentieth century, life expectancy was approximately forty-four years, but at the start of the following century, it had lengthened to roughly seventy-two years. The useful definitions of old age are not expressed in years but rather in changes of function in society and the onset of biological decline. The Egyptians defined old age as the time when a person could no longer perform the functions of an active adult and when they experienced physical infirmity. Life expectancy at birth was roughly thirty-five years, but for those living beyond five years, life expectancy was higher. At age forty a person usually was considered quite old.

Infirmities. Egyptian texts deal specifically with the...