On October 15, 1582, the Gregorian Calendar was
implemented, following a papal bull issued by Pope Gregory XIII.
Spain, Portugal, Poland, and Italy were the only nations to adopt
the calendar on this day, but it spread over the succeeding
centuries to become the international standard today.Learn more about the history of the Gregorian
calendar and view its
dates of adoption throughout the world.
On October 15, 1914, Congress passed the Clayton
Antitrust Act to clarify and supplement the
Sherman Antitrust Act of 1890.The Clayton Act outlawed trusts formed by two
companies with interlinking boards of directors, price-fixing with
businesses offering competing products, making agreements with other
businesses to control the supply of a product, and abusing power to
gain or maintain a monopoly.