In ancient Greece, athletic exercise played an important part of daily life: in fact, the Greeks credited several mythological figures with athletic accomplishments, and even male gods (especially Apollo and Herakles, patrons of sport) were commonly depicted as athletes. It is said that in the city-state of Sparta the custom of exercising naked was first introduced. Anyhow, 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, competed naked in almost all disciplines, such as stadion and various other foot races including relay race, and the pentathlon (made up of wrestling, stadion, long jump, javelin throw, and discus throw) but also boxing, wrestling, pankration. It is believed to root in the religious notion that athletic excellence was an "esthetical" offering to the gods (nearly all games fitted in religious festivals), and certainly was welcomed as a measure to prevent foul play, which was punished publicly on the spot by the judges (often religious dignitaries) with a sound lashing, also endured in the bare!
Evidence of Greek nudity in sport comes from the numerous surviving depictions of athletes (sculpture, mosaics, and vase paintings). Famous athletes were honored by a statue erected for their commemoration (such as Milo of Croton, for example). 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 could be ascribed to late-Victorian prudishness applied anachronistically to ancient times.
The word gymnasium, usually abbreviated as "gym", comes from the Greek word "gymnos", meaning "naked". Originally denoting a place for the intellectual, moral and physical education of young men as future soldiers and citizens, is another testimony of the nudity in physical exercises.
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. In fact the Greek athletes, even though naked, seem to have made a point of avoiding exposure of their glans; for example by tying a bit of string around their foreskin. In roman-occupied Jerusalem, Jews that went to the gymnasium would wear prostetic foreskins made from sheep gut in order to avoid being ridiculed for being circumcized. The Romans, although they took over much of the Greek culture, had a somewhat different appreciation of nakedness. To appear nude in public was considered disgusting except in appropriate places and context: the public baths (originally open to both sexes) and even public latrines were as popular meeting places for all as the forum.
Athletic exercises by free citizens was partly replaced by gladiatorial games performed in amphitheatres. The gladiators were mainly recruited among slaves, war captives, and death row convicts, but occasionally a free man would choose this fast lane to fame and riches. When fighting in the arena, against one another or against wild beasts, they would be armed with swords and shields, but would otherwise be partly or totally naked. Gladiators were one of many features, especially religious, Rome inherited from its highly respected Etruscan neighbours. This ancient culture even depicts warriors fighting completely naked. When Christianity in the fourth century became the State religion, gladiatorial games were soon abandoned, and the concept of nudity as "sinful" took root.
Sport in the modern sense of the word became popular only in the 19th century. Nudity in this context was most common in Germany and the Nordic countries, where body culture was very much revered (and some say, copied) by Nazi ideologues. In the nordic countries, with their sauna culture, nude swimming in rivers or lakes was a very popular tradition. 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 several naked male athletes (their genitals obscured) and was for that reason considered too daring for distribution in certain countries. Posters for the 1920 Olympics in Antwerp, the 1924 Olympics in Paris, and the 1952 Olympics in Helsinki also featured nude male figures, evoking the classical origins of the games. The poster for the 1948 London Olympics featured a classical nude sculpture of a discus thrower.