The substantial questions of macroeconomics itself are very old, going back to the origins of economics itself. But professional self-consciousness of the distinction between macroeconomics and microeconomics dates only to the 1930s. The distinction was drawn quite independently of Keynes, yet...

The theorem proving the existence of general equilibrium in a competitive economy, which necessarily involved specifying the conditions under which such an equilibrium would exist, is an extraordinary achievement of twentieth-century economics. The discovery is commonly attributed to the paper...