Flexible Gymnastic Girl

As the Roman Empire ascended, Greek gymnastics gave way to military training. The Romans, for example, introduced the wooden horse. In 393 AD the Emperor Theodosius abolished the Olympic Games, which by then had become corrupt and gymnastics, along with other sports, declined. For centuries, gymnastics was all but forgotten.
In the fifteenth century, Girolamo Mercuriale from Forlì (Italy) wrote De Arte Gymnastica, that brought together his study of the attitudes of the ancients toward diet, exercise and hygiene, and the use of natural methods for the cure of disease. De Arte Gymnastica also explained the principles of physical therapy and is considered the first book on sports medicine.
In the late eighteenth and early nineteenth century Germany, two pioneer physical educators – Johann Friedrich GutsMuths (1759–1839) and Friedrich Ludwig Jahn (1778–1852) – created exercises for boys and young men on apparatus they had designed and that ultimately led to what is considered modern gymnastics. In particular, Jahn crafted early models of the horizontal bar, the parallel bars (from a horizontal ladder with the rungs removed), and the vaulting horse.
The Federation of International Gymnastics (FIG) was founded in Liege in 1881. By the end of the nineteenth century, men's gymnastics competition was popular enough to be included in the first "modern" Olympic Games in 1896. From then on until the early 1950s, both national and international competitions involved a changing variety of exercises gathered under the rubric gymnastics that would seem strange to today's audiences: synchronized team floor calisthenics, rope climbing, high jumping, running, horizontal ladder, etc. During the 1920s, women organized and participated in gymnastics events, and the first women's Olympic competition – primitive, for it involved only synchronized calisthenics – was held at the 1928 Games in Amsterdam.