Georg Karl Julius Hackenschmidt (1 August [O.S. 20 July] 1877 – 19 February 1968) was an early 20th-century strongman, professional wrestler, writer and philosopher. He was the first free-style heavyweight champion of the world. He launched his professional career in Reval, Governorate of Estonia, and lived most of his life in London, England, where he gained the nickname of 'The Russian Lion'. Hackenschmidt is believed to be the creator of the professional wrestling version of the bear hug as well as the person who popularised the hack squat, a deadlift with arms behind the body. He was known for his impressive strength, fitness and flexibility and, later in life, wrote many books on physical culture, training and philosophy.