How it works
This is the men’s ultimate all-round test, a 10-event contest covering the whole range of athletics disciplines spread over two days.
Competitors earn points for their performance in each discipline and the overall winner is the man who accrues the most points.
The first day consists of (in order): 100m, Long Jump, Shot Put, High Jump and 400m. The second day’s events are 110m Hurdles, Discus Throw, Pole Vault, Javelin Throw and 1500m.
The forerunner of the modern Decathlon was the Pentathlon, a regular feature of the Ancient Olympics that comprised long jump, discus, javelin, sprint and wrestling.
Various versions of the event re-emerged in the 19th century to determine all-around prowess and a multi-event competition was held at the 1904 Olympic Games but the first Decathlon that resembles the current format was held in 1911, with the inaugural Olympic Games Decathlon - famously won by the legendary Jim Thorpe - taking place a year later in Stockholm.
There is also an official World record for the women's Decathlon but this is not contested at major championships.
Did you know
The scoring tables that determine how a many points a performance is worth have actually been adjusted six times since they were established in 1912, because of athletes' ever-improving abilities, equipment changes and to equate the events more accurately. The changes happened in 1920, 1934, 1950, 1962, 1977 (to take account of the growing use of electronic timing) and, most recently, 1985.
Ashton Eaton's victory at the London 2012 Olympic Games was the 13th Decathlon gold medal for the USA, who have been the most dominant nation in the event by a long way as no other country has won more than two gold medals. In similar fashion, the USA has been the most successful nation at the IAAF World Championships with seven gold medals in 13 editions.
Mathias was just 17 when he won the 1948 Olympic Games title in 1948, and he still remains the youngest ever winner of an Olympic decathlon medal.
Four years later in Helsinki, after setting his first World record in 1950, he won by the astonishing margin of 912 points with a World record tally of 7887 points to become the first man to successfully defend an Olympic Decathlon title.
Later in life, he became a successful politician and served eight years as a congressman in the US House of Representatives. He died in 2006 at the age of 75.