John Maynard Keynes, 1st Baron Keynes (pronounced /ˈkeɪnz/ "cains") (June 5, 1883 – April 21, 1946) was a British economist whose ideas, called Keynesian economics, have had a major impact on modern economic and political theory as well as on many governments' fiscal policies. He advocated interventionist government policy, by which the government would use fiscal and monetary measures to mitigate the adverse effects of economic recessions, depressions and booms. He is one of the fathers of modern theoretical macroeconomics and considered by some to be the most influential economist of the 20th century.