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"Centuries", "Centenary", "Centennial", and "Centennials" redirect here. For other uses, see Centuries (disambiguation)
Centuries (disambiguation)
Centuries are periods of one hundred consecutive years.Centuries may also refer to:* Centuries, Hythe, a Grade II listed building* Magdeburg Centuries, a celebrated ecclesiastical history...

, Centenary (disambiguation)
Centenary (disambiguation)
Centenary is an adjective form of century, a period of 100 years.Centenary may also refer to:* Centenary, Indiana, a small town in the United States* Centenary Suburbs, a group of suburbs of Brisbane, Australia...

, Centennial (disambiguation)
Centennial (disambiguation)
Centennial is of or relating to a century, a period of 100 years.Centennial may also refer to:* Smith & Wesson Centennial, a model group of snub-nosed revolvers* Centennial Class, a class of Union Pacific EMD DDA40X diesel locomotives...

, and Centennials (disambiguation)
Centennials (disambiguation)
Centennials are the 100th anniversaries of events.Centennials may also refer to:* Ayr Centennials, a junior ice hockey team* Calgary Centennials, a junior ice hockey team* Merritt Centennials, a junior ice hockey team...


A century (from the Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 centum, meaning one hundred) is one hundred consecutive year
A year is the orbital period of the Earth moving around the Sun. For an observer on Earth, this corresponds to the period it takes the Sun to complete one course throughout the zodiac along the ecliptic....

s. Centuries are numbered ordinally in English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 and many other languages (e.g. "the 7th century AD/CE").

Start and end in the Gregorian Calendar

According to the Gregorian calendar
Gregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

, the 1st century AD/CE started on January 1, 1 and ended on December 31, 100. The 2nd century started at year 101
Year 101 was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Traianus and Paetus...

, the 3rd at 201
Year 201 was a common year starting on Thursday of the Julian calendar. At the time, it was known as the Year of the Consulship of Fabianus and Arrius...

, etc. The n-th century started/will start on the year (100×n)-99 and ends in 100×n . A century will only include one year, the centennial year, that starts with the century's number (e.g. 1900 is the final year in the 19th century).

1st century BC and AD

There is no "zeroth century" in between the 1st century BC and the 1st century AD. Also, there is no year 0 AD
Year zero
"Year zero" does not exist in the widely used Gregorian calendar or in its predecessor, the Julian calendar. Under those systems, the year 1 BC is followed by AD 1...

. The Julian calendar "jumps" from 1 BC to 1 AD. The first century BC includes the years 100 BC
100 BC
Year 100 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Marius and Flaccus...

 to 1 BC
1 BC
Year 1 BC was a common year starting on Friday or Saturday of the Julian calendar and a leap year starting on Thursday of the Proleptic Julian calendar...

. Other centuries BC follow the same pattern.

Dating units in other calendar systems

Besides the Gregorian calendar, the Julian calendar
Julian calendar
The Julian calendar began in 45 BC as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year .The Julian calendar has a regular year of 365 days divided into 12 months...

, the Aztec calendar
Aztec calendar
The Aztec calendar is the calendar system that was used by the Aztecs as well as other Pre-Columbian peoples of central Mexico. It is one of the Mesoamerican calendars, sharing the basic structure of calendars from throughout ancient Mesoamerica....

, and the Hindu calendar
Hindu calendar
The hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars, as well as an Indian national calendar. Nepali calendar, Bengali calendar, Malayalam calendar, Tamil calendar, Telugu calendar, Kannada...

 have cycles of years which are used to delineate whole time periods; the Hindu calendar, in particular, summarizes its years into groups of 60, while the Aztec calendar considers groups of 52.

Centuries in astronomical year numbering

Astronomical year numbering
Astronomical year numbering
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0, the years before that are designated with negative numbers and the years after that are designated with positive numbers...

, used by astronomers, includes a year zero (0). Consequently, the 1st century in these calendars may designate the years 0 to 99 as the 1st century, years 100 to 199 as the second etc. However, in order to regard 2000 as the first year of the 21st century according to the astronomical year numbering, the astronomical year 0 has to correspond to the Gregorian year 1 BC.

Alternative naming systems

In Swedish
Swedish language
Swedish is a North Germanic language, spoken by approximately 10 million people, predominantly in Sweden and parts of Finland, especially along its coast and on the Åland islands. It is largely mutually intelligible with Norwegian and Danish...

, Danish
Danish language
Danish is a North Germanic language spoken by around six million people, principally in the country of Denmark. It is also spoken by 50,000 Germans of Danish ethnicity in the northern parts of Schleswig-Holstein, Germany, where it holds the status of minority language...

, Norwegian
Norwegian language
Norwegian is a North Germanic language spoken primarily in Norway, where it is the official language. Together with Swedish and Danish, Norwegian forms a continuum of more or less mutually intelligible local and regional variants .These Scandinavian languages together with the Faroese language...

 and Finnish
Finnish language
Finnish is the language spoken by the majority of the population in Finland Primarily for use by restaurant menus and by ethnic Finns outside Finland. It is one of the two official languages of Finland and an official minority language in Sweden. In Sweden, both standard Finnish and Meänkieli, a...

, centuries are typically not named ordinally, but according to the hundreds part of the year, and consequently centuries start at even multiples of 100. For example, Swedish nittonhundratalet (or 1900-talet), Danish and Norwegian nittenhundredetallet (or 1900-tallet) and Finnish tuhatyhdeksänsataaluku (or 1900-luku) refer unambiguously to the years 1900–1999. The same system is used informally in English. For example, the years 1900–1999 are sometimes referred to as the nineteen hundreds (1900s). This is similar to the English decade names (1980s, meaning the years 1980–1989).

See also

  • List of centuries
  • Millennium
    A millennium is a period of time equal to one thousand years —from the Latin phrase , thousand, and , year—often but not necessarily related numerically to a particular dating system....

  • Decade
    A decade is a period of 10 years. The word is derived from the Ancient Greek dekas which means ten. This etymology is sometime confused with the Latin decas and dies , which is not correct....

  • Lustrum
    A lustrum was a term for a five-year period in Ancient Rome.The lustration was originally a sacrifice for expiation and purification offered by one of the censors in the name of the Roman people at the close of the taking of the census...