The Game of Football

Football is a family of team sports that involve, to varying degrees, kicking a ball to score a goal. Unqualified, the word football is understood to refer to whichever form of football is the most popular in the regional context in which the word appears. Sports commonly called 'football' in certain places include: association football (known as soccer in some countries); gridiron football (specifically American football or Canadian football); Australian rules football; rugby football (either rugby league or rugby union); and Gaelic football. These different variations of football are known as football codes.

Various forms of football can be identified in history, often as popular peasant games. Contemporary codes of football can be traced back to the codification of these games at English public schools during the nineteenth century. The expanse of the British Empire allowed these rules of football to spread to areas of British influence outside of the directly controlled Empire, though by the end of the nineteenth century, distinct regional codes were already developing: Gaelic football, for example, deliberately incorporated the rules of local traditional football games in order to maintain their heritage. In 1888, The Football League was founded in England, becoming the first of many professional football competitions. During the twentieth century, several of the various kinds of football grew to become some of the most popular team sports in the world.

Common rules among the sports include:
Two teams of usually between 11 and 18 players; some variations that have fewer players (five or more per team) are also popular.
1. A clearly defined area in which to play the game.
2. Scoring goals or points, by moving the ball to an opposing team's end of the field and either into a goal    area, or over a line.
3. Goals or points resulting from players putting the ball between two goalposts.
4. The goal or line being defended by the opposing team.
5. Players being required to move the ball—depending on the code—by kicking, carrying, or hand-passing the ball.
6. Players using only their body to move the ball.

The Middle Ages saw a huge rise in popularity of annual Shrovetide football matches throughout Europe, particularly in England. An early reference to a ball game played in Britain comes from the 9th century Historia Brittonum, which describes "a party of boys ... playing at ball". References to a ball game played in northern France known as La Soule or Choule, in which the ball was propelled by hands, feet, and sticks, date from the 12th century.

The early forms of football played in England, sometimes referred to as "mob football", would be played between neighboring towns and villages, involving an unlimited number of players on opposing teams who would clash en mass, struggling to move an item, such as inflated animal's bladder to particular geographical points, such as their opponents' church, with play taking place in the open space between neighboring parishes. The game was played primarily during significant religious festivals, such as Shrovetide, Christmas, or Easter, and Shrovetide games have survived into the modern era in a number of English towns (see below).

The first detailed description of what was almost certainly football in England was given by William Fitz Stephen in about 1174–1183. He described the activities of London youths during the annual festival of Shrove Tuesday: