SOURCE: “The Variety of Calendars,” in Mapping Time: The Calendar and Its History, Oxford University Press, 1998, pp. 89-109.

In the following excerpt, Richards summarizes the types, characteristics, and sources of various calendars.

Empirical Calendars

Men have ordered their affairs by the phases of the moon and the seasons for as long as records exist. Even before calendars had been invented they could have told their wives that they would be back three days after the next full moon or remarked that their son was born three winters ago. Such perhaps were the beginnings of calendars. Later, men counted the days between moons and solstices, and were better able to anticipate a day in the future or to remember the past. But they still needed to observe the moon or the solstices to determine when a new month or a year began. As astronomy developed, it became possible to...