In January 897, Pope Stephen VI convened the so-called Cadaver Synod, exhuming the nine-months-dead body of Pope Formosus, propping it on a throne, and putting it on trial for alleged violations of church law. The corpse was found guilty, stripped of its vestments, mutilated, and thrown into the Tiber River, one of the strangest episodes in papal history and a symptom of the era's brutal power struggles.

Nicolaus Copernicus died on February 18, 1543, in the Polish town of Frombork, reportedly having just received a printed copy of his life's work, 'De revolutionibus orbium coelestium.' The book argued the Earth orbited the Sun rather than the reverse, a claim so radical that Copernicus delayed publishing it for decades. His death spared him the theological firestorm that engulfed later heliocentrists like Galileo.

In February 1597, Toyotomi Hideyoshi ordered a second full-scale invasion of Korea after peace negotiations with Ming China collapsed. Japanese forces, having previously withdrawn to the southern coast following setbacks including Admiral Yi Sun-sin's naval victories, renewed their offensive, plunging the Korean peninsula back into a war that devastated the countryside and reshaped East Asian geopolitics.

Historical calendar confusion aside, February 18 has been cited in several early American almanacs and colonial records referencing Washington-related dates due to the Julian-to-Gregorian transition of 1752, which shifted dates by eleven days and created decades of confusion in colonial recordkeeping across British America.

On February 18, 1918, Arthur Scherbius filed a patent for an electro-mechanical cipher machine using rotating wired disks to scramble letters into code. Commercialized in the 1920s and later adopted by the German military, the device evolved into the Enigma machine, whose codes British codebreakers at Bletchley Park — including Alan Turing — famously cracked during World War II.

On February 18, 1930, Clyde Tombaugh, examining photographic plates at Lowell Observatory in Flagstaff, Arizona, noticed a tiny point of light that had shifted position between exposures taken two weeks apart. The object was later named Pluto, fulfilling astronomer Percival Lowell's decades-old quest for a hypothesized 'Planet X.' It was reclassified as a dwarf planet in 2006.

In mid-February 1967, in the weeks following the January 27 Apollo 1 launch pad fire that killed astronauts Gus Grissom, Ed White, and Roger Chaffee, NASA and congressional review boards were deep in investigations exposing dangerous design flaws, including the capsule's pure-oxygen atmosphere and an inward-opening hatch that trapped the crew, forcing sweeping redesigns before any further crewed Apollo flights.

Nelson Mandela was released from Victor Verster Prison on February 11, 1990; in the days that followed, including February 18, South Africa and the world absorbed the scale of the moment as Mandela addressed massive crowds in Cape Town and began the transition toward the African National Congress's return to open political life and negotiations that would end apartheid.