A bunch of random events scattered across the years...
May 7, 1429 - Joan of Arc ends the siege of Orleans after pulling an arrow from her shoulder and returning to the battle. This marked a turning point in the Hundred Years War.
May 7, 1812 - English poet Robert Browning was born.
May 7, 1915 - During World War I the Cunard liner Lusitania was torpedoed by a German u-boat off the coast of Ireland. Roughly 1,200 lives were lost. The death of 128 Americans brought the US to the verge of war with Germany.
May 7, 1945 - Germany signed an unconditional surrender, ending six years of war in Europe.