Saint-Louis would have been a tiny village called Birsen, which has now disappeared. The name Saint-Louis comes from the name of King Louis IX of France. Legend has it that he enjoyed resting in the fields located in the rue de Mulhouse, near the rue du Rail. Saint-Louis is a "young town", just over 300 years old, which officially came into existence on November 28, 1684, by order of Louis XIV. But Saint-Louis was colonized very early on. Tombs dating back to 1500 B.C. and a Gallic treasure dating back to 80 B.C. have been discovered here.