Arabic numerals and the decimal system are introduced in Europe. Nitpickers immediately start carping about the lack of a zero. First meeting of the House of Commons, the forerunner of most modern democratic assemblies including our own Congress. First toll road opens. Hairbrush and toothpaste sales boom.
China discontinues use of paper money because of inflation.
Hundred Years' War begins between England and France, stumping trivia players for centuries to come. Cathedral of Notre Dame completed after 182 years of construction. Delay blamed on large number of workers standing around in orange vests doing nothing. Hundred Years' War suspended until men are well enough to kill each other again. Entire Chinese population makes vases.