18 May History
- 526 - St. John I ends his reign as Catholic Pope.
- 1643 - Queen Anne, the widow of Louis XIII, is granted sole and absolute power as regent by the Paris parliament, overriding the late king's will.
- 1652 - A law is passed in Rhode Island banning slavery in the colonies but it causes little stir and seems unlikely to be enforced.
- 1792 - Russian troops invade Poland.
- 1802 - Britain declares war on France.
- 1804 - Napoleon Bonaparte becomes the Emperor of France.
- 1828 - The Battle of Las Piedras, between Uruguay and Brazil, ends.
- 1860 - Abraham Lincoln is nominated for president.
- 1864 - The fighting at Spotsylvania in Virginia, reaches its peak at the Bloody Angle.
- 1896 - The Supreme Court's decision on Plessy v. Ferguson upholds the "separate but equal" policy in the United States.
- 1904 - Brigand Raizuli kidnaps American Ion H. Perdicaris in Morocco.
- 1917 - The U.S. Congress passes the Selective Service act, calling up soldiers to fight World War I.
- 1931 - Japanese pilot Seiji Yoshihara crashes his plane in the Pacific Ocean while trying to be the first to cross the ocean nonstop. He is picked up seven hours later by a passing ship.
- 1933 - President Franklin Roosevelt signs the Tennessee Valley Authority Act.
- 1942 - New York ends night baseball games for the rest of World War II.
- 1944 - The Allies finally capture Monte Cassino in Italy.
- 1951 - The United Nations moves its headquarters to New York city.
- 1969 - Two battalions of the 101st Airborne Division assault Hill 937 but cannot reach the top because of muddy conditions.
- 1974 - India becomes sixth nation to explode an atomic bomb.
- 1980 - After rumbling for two months, Mount Saint Helens, in Washington, erupts 3 times in 24 hours.
18 May Birthdays
- 1836 - Wilhelm Steinitz, chess champion.
- 1868 - Nicholas II, the last Russian czar.
- 1872 - Bertrand Russell, English mathematician, philosopher and social reformer.
- 1897 - Frank Capra, film director (It's A Wonderful Life).
- 1902 - Meredith Willson, composer and lyricist (The Music Man).
- 1911 - Joseph Vernon "Big Joe" Turner, blues singer.
- 1918 - John Paul II [Karol Jozef Wojtyla], Roman Catholic pope.
- 1919 - Margot Fonteyn, English ballet dancer.