Anne Robert Jacques Turgot, Baron de l'Aulne ( toor-GOH; French: [tyʁgo]; 10 May 1727 – 18 March 1781), commonly known as Turgot, was a French economist and statesman. Sometimes considered a physiocrat, he is today best remembered as an early advocate for economic liberalism. He is thought to have been the first political economist to have postulated something like the law of diminishing marginal returns in agriculture.
Source : Wikipedia