From humble beginnings at Rugby School in the early 1800s to the modern day game with more than 4 billion fans worldwide, rugby is a fascinating example of an accidental invention that went viral.

To most rugby fans the defining moment that gave the sport its name is almost sacrosanct. It happened during a ‘footballing’ encounter of sorts on an eight-acre plot owned by Rugby School in 1823 when, against the rules, William Webb Ellis caught the ball and ran forward with it in his arms. That incident led to the formation of Rugby Union and then Rugby League: ­ games that are now played all over the world.

But was William Webb Ellis really the “inventor” of the modern game? Tradition says he was, but over the years doubts have been raised. Tony Collins, in his book The Oval World, A Global History of Rugby, makes an interesting observation. He writes: “No one would have been more surprised than William Webb Ellis himself by the claim that he ‘invented’ rugby by picking up the ball.” He adds that Ellis, who became an Anglican clergyman, died in France 49 years later “oblivious to his apparently historic achievement.”

Collins points to another pupil from the Warwickshire school, Jem Mackie, who was renowned for running ‘illegally’ with the ball in the 1830s. Could he have taken Ellis’s place in the mythology of rugby had he not been expelled following an “unexplained incident”? When an investigation was set up in 1895 by the Old Rugbeian Society to look at the origins of the game, they found no evidence to support the Ellis story. Yet they let it be known that Ellis was the ‘originator’ of the sport.

The new game flourished and Collins believes that the highly successful book Tom Brown’s Schooldays, written by former Rugby School pupil Thomas Hughes, played a huge part. Hughes wrote about life at the school and how its headmaster Thomas Arnold linked playing rugby with the character-forming principles a young gentleman would need in later life. It was published in 1857 and written for Hughes’s son Maurice, who was about to join the school.

The book was a bestseller and influenced other schools and universities to follow Rugby’s example and the game spread quickly. Was that why the Old Rugbeian Society stayed focused on Ellis? It would seem so, but there was a tragic downside to the book’s success. Sadly, two years after it was published, Maurice died.

The school had legalised running with the ball in 1842 before publishing the first written rules of the game three years later. Yet, the roots of rugby can be traced back thousands of years. In China, there was a game called Cuju in which the ball was kicked over a net held up by poles while, in Roman times, Harpastum was popular. It was said to be violent and physically demanding and its rules were similar to a Greek game called Phaininda.

In the Middle Ages, ‘folk football’ was played in Great Britain and across Europe. Teams made up from the inhabitants of a town or village scrapped for a ball which could be kicked or carried along streets, through fields and streams and even over hedges in a bid to score a goal. The players loved it but some ‘non-believers’ tried to ban it, preferring instead the quiet life. They also worried that injuries might deplete the local workforce.

Shrove Tuesday became the popular day for these events and although rules varied from district to district alcohol helped to ensure a successful day of conflict. It plays its part today as rugby fans love to savour pre-match or post-match pints in pleasant surroundings.  (Professional players, of course, tend to sup up afterwards, not before!). Fittingly, William Webb Ellis plays his part here too. There are at least two strategically-placed pubs in England bearing his name. One is in Rugby and the other in Twickenham, near to its famous national stadium.

As Folk Football evolved it was always more like rugby than soccer and those differences were recognised in 1863 when the Football Association was formed. The birth of the Rugby Football Union followed in 1871 although an internal dispute, mainly over professionalism, led to a split by northern clubs and Rugby League’s arrival in 1895. Ironically, 100 years later, Rugby Union turned professional. Both codes prospered and the inaugural Rugby League World Cup in 1954 was followed by union’s Rugby World Cup In 1987 and England’s historic victory in 2003.

Women’s rugby is said to have evolved from a fateful moment in 1887 at the Portora Royal School in Enniskillen, Northern Ireland. The school team were a “man” short and Emily Valentine stepped in to score a try on her debut. No doubt her dad, the school’s assistant headmaster, enjoyed the occasion and the women’s game gradually flourished. In 1983, the Women’s Rugby Football Union was formed and the first Women’s World Cup followed in 1991. Nine years later, the Women’s and Girl’s Rugby League was established.

Today millions of people in more than 100 countries play both codes and September’s Rugby World Cup in Japan is the first to be held in Asia. It is claimed that 4.2 billion TV viewers watched the 2007 Rugby World Cup. That’s quite a legacy for a man, who achieved worldwide fame without knowing it, after allegedly catching and running with a ball against the rules of a game.