According to the principle of 'To each according to his contribution', during the transition of a society from capitalism to socialism and then to communism, individuals should be rewarded for the amount they contribute to society. Economists such as David Ricardo (1772-1823) had this idea. Ricardo founded a movement that is known as Ricardian socialism today. Many people in the labour movement had this idea too. Ferdinand Lassalle (1825–1864) and Eugen Dühring (1833-1921) expressed such ideas towards Leon Trotsky. Despite this, Vladimir Lenin was the first person to say that this element is fundamental to Marxist theory.