This week in 1804, the Louisiana Territory transferred from French to U.S. sovereignty, with the change marked by a ceremony in St. Louis. The territory had actually changed hands before, from France to Spain and then, as late as 1800, back to France. France’s First Consul, Napoleon Bonaparte (later emperor), had planned to reestablish a French colony in North America, but he found himself short of resources, thanks to troubles at home and war with Britain (and ultimately just about everyone else). Hard up for cash, Napoleon had sold the Louisiana Territory to the U.S.’s President Thomas Jefferson. The two republican leaders’ original plan just involved the purchase of New Orleans. But in 1803, French Treasury Minister Francois Barbe-Marbois had offered the whole, vast Louisiana Territory to the American negotiators, James Monroe (later President) and Robert Livingston. They jumped at it. In fact, President Jefferson exceeded his authority by committing to the purchase without Congress’ consent, but he could not pass up the chance to double America’s possessions.

The St. Louis ceremony this week in 1804 is called Three Flags Day. First, Spain formally transferred the territory back to France, symbolically completing the transaction agreed in 1800. The Spanish lowered their flag, and the French raised theirs – for 24 hours. Then, the French lowered their flag and America’s stars and stripes rose over the Louisiana Territory – presumably forever.