How did saint Louis Missouri get its name?

The city was named after King Louis IX of France.

Laclede named his town to honor King Louis XV's patron Saint---Saint Louis.

Louis IX of France was the only French King to become a saint in 1297.

He financed and fought in the Seventh and Eighth crusade.

Financing was obtained from the Knights Templar because of the Monastery being on the Temple Mount---Mount Moriah in Jerusalem, currently the site of the Dome of the rock a holy site of Islam.