In ancient Greece, athletic exercise played an important part. In fact, the Greeks credited several mythological figures with athletic accomplishments.
It was in the city-state of Sparta that the custom of exercising naked was first introduced. From there, it spread to the whole of Greece, and the athletes from all its parts, coming together for the Olympic Games and the other Panhellenic Games, would compete naked in almost all disciplines, such as boxing, wrestling, pankration, stadion and various other foot races, and the pentathlon (made up of wrestling, stadion, long jump, javelin throw, and discus throw). However, they did not perform in the nude during chariot races.
Evidence of Greek nudity in sport comes from the numerous surviving depictions of athletes (sculpture, mosaics, and vase paintings). Famous athletes were honoured with a staue erected for their commemoration (see Milo of Croton). A few writers have insisted that the athletic nudity in Greek art is just an artistic convention, finding it unbelievable that anybody would have run naked. This view should be ascribed to late-Victorian prudishness applied anachronistically to ancient times.
The word gymnasium (from Greek gymnasion), originally denoting a place for education of young men, is another testimony of the nudity in physical exercises; the word being derived from Greek gymnos, mening "naked". The more recent form gym is an abbreviation of gymnasium.
In Hellenistic times, Greek-speaking Jews would sometimes take part in athletic exercises. They were then exposed to ridicule because they were circumcised - a custom which was unknown in the Greek tradition.
The Romans, although they took over much of the Greek culture, had a different evaluation of nakedness. To appear naked in public was considered disgusting. However, athletic exercises by free citizens had partly been replaced by gladiatorial games performed in amphitheatres. The gladiators were recruited among slaves, war captives, and convicts. When fighting in the arena, against one another or against wild beasts, they would be armed with swords, shields, etc., but would otherwise be partly or totally naked (see Gladiator for particulars).
When Christianity in the fourth century became the state religion, gladiatorial games were soon abandoned, and the concept of nudity as sinful took over.
Sport in the modern sense of the word became popular only in the 19th century, but nothing approaching nakedness was practised. An exception was in Sweden, where swimming in rivers or lakes was very popular. In the summer, there would be wooden bathhouses, often of considerable size accommodating numerous swimmers, built partly over the water. Hoardings prevented the bathers from being seen from outside. Originally the bathhouses were for men only; today there are usually separate sections for men and women.
For the Olympic Games in Stockholm in 1912, the official poster was created by a distinguished artist. It depicted a naked Swedish athlete and was for that reason considered too daring for distribution in certain countries.
A group from southern U.S., having been invited in the 1950s to participate in a university students' swimming competition in Stockholm, was surprised to find at their arrival at the (indoors) swimming pool that their swimming trunks were out of place: they had to swim in the nude like everybody else.