Exercise was hot and inconvenient in the Victorian era, with its high collars and knee-length coats, so it's no surprise that many people opted out. Jorgen Peter Muller, a Danish athlete and gymnastic educator, set out to change that. Muller had such great success that he was knighted by the king of Denmark in 1919.
Muller believed that sun, water and air were the keys to good health. Based on his ideas, he developed a home gym that people used for 15 minutes a day, wearing as little clothing as possible, with open windows. The routine finished with a cold shower.
The program worked extraordinarily well for Muller, who went on to win 134 prizes across almost every branch of sports. In 1892, he set records in running, walking, discus, hammer-throwing and shot-putting at the Danish Athletic Games. The next year, he won the Decathlon competition.
In 1904 Muller released his bestselling book My System, based on the philosophies and 18 exercises he used. The book was translated into 24 languages and became compulsory reading in the British Army and Navy during WWI. You can still purchase a copy today.
In 1912, he established the Muller Institute in London. Over a million students visited, including the Duke of Windsor and the Prince of Wales.