The history of advertising in Britain has been a major part of the history of its capitalist economy for three centuries. It became a major force as agencies were organized in the mid-19th century, using primarily newspapers and magazines. In the 20th century, It grew rapidly with new technologies, such as direct mail, radio, television. In the late 19th century, home-based British agencies were swallowed up and became branches of international firms, but London remains one of the world's most important advertising centers. Radical changes have come recently because of the new roles for the Internet and smart phones. For current conditions see Advertising.