Australian rules football, officially known as Australian football, football, footy or Aussie rules or AFL, after the Australian Football League, the only fully professional Australian rules football league) is a sport played between two teams of 18 players on the field on either an Australian rules football ground, a modified cricket field or another modified sports venue.

The objective of the game is to score points by passing the ball through the team's goal. The main way to score points is by kicking the ball between the two major goal posts. The team with the higher total score at the end of the match wins unless either a draw is declared or a tie-break is used.

During most play, players may position themselves anywhere on the field and use any part of their body to move the ball. The primary methods are kicking, handballing and running with the ball. There are rules on how the ball can be handled: for example, players running with the ball must intermittently bounce or touch it on the ground. Throwing the ball is not allowed and players must not get caught holding the ball. Possession of the ball is in dispute at all times except when a free kick is paid. A distinctive feature of the game is the mark, where players anywhere on the field who catch a ball from a kick (with specific conditions), are awarded a free kick.

Australian rules is a contact sport, in which players can tackle using their hands or use their whole body to obstruct opponents. Dangerous physical contact (such as pushing an opponent in the back), interference when marking and deliberately slowing the play are discouraged with free kicks, distance penalties or suspension, depending on the seriousness of the infringement. Frequent physical contests, spectacular marking, fast movement of both players and the ball and high scoring are the game's main attributes.

Details of the game's origins in Australia are obscure and still the subject of much debate. Australian rules football became organised in Melbourne in May 1859, when the first laws of the game were published by the Melbourne Football Club. Australian football is a major participation and spectator sport in Australia. The sport is also played at amateur level in several countries and in several variations.

The most prestigious competition is the Australian Football League (AFL), culminating in the annual AFL Grand Final, currently the highest attended club championship event in the world. The rules of Australian football are governed by the AFL Commission with the advice of the AFL's Laws of the Game Committee.

Origins

As early as 1841, there is documented evidence of "foot-ball" being played in metropolitan and country Victoria as well as mention of early matches in Adelaide (1843) and southern Van Diemen's Land (Tasmania). While the exact rules being played in these matches are unknown they may have shared similarities and influences.

In 1858 English public school football games began to be played in Melbourne and surrounding districts. The earliest known such match was played on 15 June 1858 between Scotch College and Melbourne Grammar School on the St Kilda foreshore.

A letter by Tom Wills was published in Bell's Life in Victoria & Sporting Chronicle on 10 July 1858, calling for a "foot-ball club", or some other "athletic game", with a "code of laws" to keep cricketers fit during winter. This letter is regarded by many historians as being a catalyst for the development of a new code of football in 1859 today known as Australian football.

On 31 July, a knock-a-bout match at Yarra Park was played between a "St Kilda scratch team" and "Melbourne scratch team". Trees were used for goal posts and there were no boundaries and the match lasted from 1pm until dark. There were no rules and fights frequently broke out. Melbourne being a relatively young city, the majority of the early players were migrants and the media of the time noted that participants of each nationality played the game their own distinctive way: the English played in a fashion that resembled rugby football, the Scots played recklessly, and the Irish played in a fashion that resembled the Irish sport of Gaelic football. How the Welsh played is unknown.

Another significant milestone in the sport's development was a match between Melbourne Grammar School and Scotch College, which began on 7 August 1858 at Richmond Park, was umpired by Wills and Macadam, and which also involved Scotch College headmaster Thomas H. Smith. A second day of play took place on 21 August and a third, and final, day on 4 September. While the full rules that were used is unknown, some details of the match survived. It was played with a round ball, the distance between the goals was approximately half a mile (approximately four times longer than the modern Melbourne Cricket Ground playing surface), there were 40 players per side and one goal each side was scored with the game being declared a draw. The two schools have competed annually ever since for the Cordner-Eggleston Cup.

Gradually the game known at first as "Melbourne rules" became "Victorian rules" and then "Australian rules" or "Australasian rules" gained roots in other Australasian colonies, beginning with South Australia (1860) Tasmania (1864), Queensland (1866), and New Zealand (1871). In 1877, the sport's first governing bodies, the South Australian Football Association and the Victorian Football Association were formed on 30 April and 17 May respectively. The game began to be played in New South Wales in 1877, in Western Australia in 1881 (During the 1880s, young men sent to school in Adelaide brought the game home when they had finished their education—more came from the eastern states later in the WA gold rush) and the Australian Capital Territory in 1911. By 1916, the game was first played in the Northern Territory, establishing a permanent presence in all Australian states and mainland territories.

The South Australian National Football League (SANFL), formerly named the South Australian Football Association, and the West Australian Football League (WAFL), formerly named the Western Australian Football Association, were strong, separate competitions by the 1890s. However, late in the century the code began to decline in New South Wales and Queensland largely due to competition with other more popular football codes, as well as interstate rivalries and the lack of strong local governing bodies. In the case of Sydney, denial of access to grounds and the loss of professional players to other football codes directly inhibited to the game's growth.

The first inter-colonial match had been played between Victoria and South Australia on 2 August 1879.