The first Oktoberfest celebrated the wedding of Crown Prince Ludwig (later King Ludwig I) and Princess Therese of Saxe-Hildburghausen on Oct. 12, 1810.
So why September? I finally decided to look it up. In turns out the informal roots of Oktoberfest started back in the 15th century, with beer, according to the German Beer Institute.
The brewing season in Bavaria ran from October to March. Beer brewed during the hot season tasted bad, so in late winter, brewers would work extra hard to make enough beer to last all summer. The high alcohol content and storage in casks in cool cellars and caves would preserve it.
After the summer’s grain was harvested, brewers needed to empty those casks to make room for the October start of the brewing season. People were happy to help.
In 1810, by the date the royal wedding made Oktoberfest official, there wasn’t much beer left. Horse racing was the main event there, and Prince Ludwig repeated the races every year on his anniversary. Over the years, the festival was extended and combined with finishing off the March beers, evolving into today’s party attended by millions around the world.