Rugby

Rugby is said to have originated at Rugby School in Warwickshire, England, in 1823 when during a game of football, William Webb Ellis decided to pick up a ball and go with it. Although there is very little evidence to support this theory, the Rugby World Cup Trophy is now named after William Webb Ellis.
In 1863 a collection of boarding schools and clubs decided upon a rule set and 1871 Rugby Football Union was officially formed. That same year, the first ever international match was played between England and Scotland with Scotland taking the win 1-0.

Summer Olympics

In 1900, rugby union was introduced to the Summer Olympics by Pierre de Coubertin, who had previously refereed the first French domestic championship as well as France's first international game. France, Germany and Great Britain all entered teams for the oplympics, and France won gold by defeating both opponents.
Rugby actually drew the largest crowd at that particular games - it was next played at the 1908 games in London, with Australia winning, by defeating Great Britain.
Even though rugby drew some of the biggest crowds at the games, it was eventually dropped in 1924.

By 1908 all three major Southern Hemisphere nations (New Zealand, Australia and South Africa) had formed teams and sent them on international trips to play against the Northern Hemisphere nations. As a side fact, the first time the Haka was performed by New Zealand prior to a match was in 1905, which the Welsh responded to by having Teddy Morgan sing the Welsh national anthem. Soon enough the crowd joined in, which was the first time a national anthem was sung prior to a sporting event.