However as other nations industrialized and social and political changes took place in the Empire, the idea of colonization and imperialism fell out of favour. In addition, the consequences of fighting two world wars in the 20th century within a relatively short amount of time hastened the decline of the Empire. The movement for self-determination of Britain's colonies started in the late 19th century and was well underway by the 1920s, seen for example through the emergence of the Indian National Congress in 1885 and the Balfour Declaration of 1926.