Rugby and its cousin Association Football (more commonly referred to as "football" or "soccer") may not seem to be related, but they do share a common history. The term "football" does not (as many assume) imply a sport where the ball is played by the foot, but rather a sport which is played on foot (unlike sports such as polo, which are played on horseback). Rugby's official (though often debated) history dates back to 1823, although various forms of sport resembling the game previously existed throughout medieval Europe.
The legendary story/myth about the origin of Rugby football — whereby a young man named William Webb Ellis "took the ball in his arms [i.e. caught it] and ran" while playing Rugby School's already distinctive version of football (not to be confused with association football, which was codified much later) in 1823 — has little evidence to support it. Pundits have dismissed the story as unlikely since it was first given the School's seal of approval following an official investigation by the Old Rugbeian Society in 1895. However, the story has entered into legend, and the trophy for the Rugby Union World Cup bears the name of "Webb Ellis" in his honour and a plaque at the School commemorates the "achievement".
Various kinds of football have a long tradition in England and football games had probably taken place at Rugby School for 200 years before three boys published the first set of written rules (in 1845). At the time, a set of rules would be agreed between two teams before a match. Teams which competed against each other regularly would tend to agree to play similar rules.
Rugby backs can be identified because they generally have clean jerseys and identifiable partings in their hair... come the revolution the backs will be the first to be lined up against the wall and shot for living parasitically off the work of others.