The Sherman Antitrust Act is a United States antitrust law passed by Congress in 1890. It was the first federal statute to limit cartels and monopolies. The Act prohibits any contract, combination, or conspiracy in restraint of trade, and it also prohibits monopolies and attempts to monopolize the market. It was named after Senator John Sherman, its principal author. The Act was intended to be a comprehensive charter of economic liberty aimed at preserving free and unfettered competition as a rule of trade.