The word caid originally referred to the ball which was used. It was made out of animal skin, with a natural bladder inside.
Caid is believed to have influenced the modern sport of Gaelic football the rules of which were officially published in 1887 and is now organised and governed by the Gaelic Athletic Association (GAA) as an amateur sport.
There is some evidence that caid was taken around the world by the Irish diaspora, and some historians argue that it may have also played some part in the origins of Australian rules football, although such a relationship is controversial and the subject of debate.
The first recorded mention of football in Ireland was in 1308, when John McCrocan, a spectator at a football game at Newcastle, County Down, was charged with accidentally stabbing a player named William Bernard. Football games are mentioned in the Statute of Galway, 1527, which allowed the playing of football and archery, but banned "'hokie' — the hurling of a little ball with sticks or staves", as well as other sports. The Sunday Observance Act of 1695 imposed a fine of one shilling for anyone found playing. Despite this, the earliest recorded football match in Ireland was one between Louth and Meath, at Slane, in 1712.
Caid was especially popular in rural areas, such as the Dingle Peninsula of Kerry and Eigeen in west Cork. One observer in the mid-19th century, Father W. Ferris, described two main forms of caid during this period: the "field game" in which the object was to put the ball through arch-like goals, formed from the boughs of two trees, and; the epic "cross-country game" which took up most of the daylight hours of a Sunday on which it was played, and was won by one team taking the ball across a parish boundary. Both of these were rough and tumble contact sports in which "wrestling", pushing and the holding of opposing players was allowed. It was usually played by teams of unlimited numbers, representing communities, until a clear result was achieved or the players became too exhausted to continue.
These games appear to have been similar to the traditional Welsh game of cnapan, which was played by teams of up to 1,000 men from adjacent parishes. Cnapan, however, was played with a hard ball and thus involved no kicking; it was strictly a game in which the ball was passed or smuggled from one player to another, with the object of getting it to the opposing team's parish church porch or to some other agreed destination. An inter parish mob football game similar to cnapan called Hyrlîan (In English Hurling) is still played in Cornwall on dates that coincide with religious festivals such as Shrove Tuesday.
By the late 19th century, caid was in steep decline and was threatened with extinction, spurring the formation of the GAA which published official rules for the game in 1887 also adopting aspects of the earlier codified sport - hurling.