Century

A century is one hundred of something, usually one hundred consecutive years.

This page is about centuries as units of time. For other meanings of the term, please see Century (disambiguation).

• In all dating systems, centuries are essentially numbered ordinally, as time is a purely relative notion (its physical existence, though indispensable for our understanding of reality, still remains unproven in theory). Thus, one speaks of the First Century of the Common Era, never of Century Zero.

• There is considerable disagreement about whether to count the centennial year (i.e. 2000) as the first or last year of a century. This confusion is documented for every centennial year from 1500 onward, and almost certainly arises from the introduction of Arabic numerals and the concept of zero to Western Europe in the twelfth century.

The oldest dating systems were regnal, and considered the date as an ordinal, not a cardinal number. Thus, one speaks of the first year of the reign of King so-and-so. Obviously, the century problem does not arise in such systems. Somewhat later, systems arose dating from the founding of a dynasty, city or religion, and these continued ordinal, rather than cardinal, counting. Thus Ab Urbe Condita counts the Year 1 as the founding of Rome; Anno Domini as the first full year of Jesus Christ's life; the Islamic Calendar as the year of the Hejira, so it is also latinized as Anno Hejira.

More modern systems of dating, (such as the astronomical calendar, see proleptic Gregorian calendar) begin with a year zero. In these cardinal dating systems, it is perfectly logical to use 0 to 99 as the first century, and to regard 2000 as the first year of the twenty-first century.

• The equivalent chronological terms in various other (especially Romance) languages, including secolo (Italian; there the established tradition is to count 00-99 and to name the century after the third-last digit in each year within each millennium, e.g. seicento for the 1600s), siècle (french), stem from another Latin word, saeculum.

This encyclopedia has a page for each century; see Centuries.

See also

• decade (ten years)
• eon (undetermined)
• era (undetermined)
• indictio (fifteen years in Roman fiscality)
• lustrum (five years)
• Millennium (ten centuries)

Useful Source

"The Battle of the Centuries", Ruth Freitag, U.S. Government Printing Office. Available from the Superintendent of Documents, PO Box 371954, Pittsburgh, PA 15250- 7954. Cite stock no. 030-001-00153-9.