The history of Olympic swimming dates back to the birth of the modern Olympics in 1896. At that time, there were four swimming events, each one for men only, consisting of the 100m freestyle, 400m freestyle, 1200m freestyle, and a separate category open only for sailors in the Greek Royal Navy-the 100m freestyle.
Swimming has existed since the days of the caveman but it didn't become popular as a competitive sport until the early 1800's. An English organization known as the National Swimming Society of Great Britain, started holding swimming competitions in 1837. The popularity of these competitions grew steadily so swimming was one of the sports included in the 1896 Summer Olympics held in Greece.
Instead of a pool, which is used for today's races, the first competitors swam in the Mediterranean Sea. They were taken out by boat to the designated length of the race and had to swim in the frigid water, in April, back to shore. Swimmers used a form of the breaststroke. When the Summer Olympics were in Paris, France in 1900, swimming races took place in the Seine River. A 100m long pool was used in 1908 when the Summer Games were held in London, England. The 50m pool was first used in the Summer Games in Paris, France, in 1924. This 50m pool is now the standard size.
Women's Olympic swimming competitions didn't start until the 1912 Summer Games held in Stockholm, Sweden. Today, men's and women's competitions in swimming are of the same disciplines with one exception-the 1500m long distance race for men is reduced to the 800m long distance race for women.