The Sherman Anti-Trust Act was passed by Congress in 1890 to prevent the formation of monopolies and any other contracts or agreements that resulted in a "restraint of trade."
This constitutes a antitrust law introduced with the aim of regulating competition among enterprises. President Benjamin Harrison was in office when the Congress passed this law in 1890.
This law forbids any anticompetitive agreements as well as unilateral conduct that monopolizes the market.