French members of the Crusade-era chivalric order the Knights Templar, including Grand Master Jacques de Molay, were arrested upon the orders of King Phillip IV of France on October 13, 1307. The group was baselessly accused of multiple offenses, including idolatry and homosexual acts. The Templars would be tried for these offenses before being disbanded officially by Pope Clement V in 1312. Learn more about the Knights Templar.

On October 13, 1952, the US Supreme Court announced that it had declined to grant certiorari in the appeal of Julius and Ethel Rosenberg, condemned to death for conspiracy to commit atomic espionage for the Soviet Union. Justice William O. Douglas eventually granted a stay of execution on June 17, 1953, but that order was vacated by the full Court and the Rosenbergs were executed on June 19, 1953. Learn more about the Rosenbergs' case from the Eisenhower Presidential Library.

On October 13, 1884, Greenwich Mean Time (GMT) was declared universal time by the International Meridian Conference, a gathering of 25 nations from around the globe.
Read the proceedings of the International Meridian Conference from Project Gutenberg.