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.