Florissant grew from one of Missouri's oldest settlements after French trappers following the Riviere le Biche, or Cold Water Creek, settled in a rich valley in the late 18th century. Spanish rulers called the area St. Ferdinand, while French settlers called it Fleurissant, meaning flowering or blooming. Francois Dunegant formed Florissant's first civil government and in 1786 was commissioned by the Spanish government as the village's first military and civil commandant. A Spanish census counted 40 people and seven plantations there in 1787. The original village pattern remained visible in Old Town, where small French homes stood on quarter-block lots with animal pens and kitchen gardens, while the land between Coldwater Creek and the Missouri River was divided into long narrow Common Fields and the surrounding open forest and fields served as Commons for firewood, grazing, and gathering. The Spanish king granted land to the inhabitants of St. Ferdinand for what became Spanish Land Grant Park, once the Place d'Arms where militia drilled. From 2004 to 2006, an archaeological excavation at the site of the original 1789 St. Ferdinand Church uncovered about 10,000 items and the complete footprint of the presbytery, confirmed that only the cemetery headstones had been moved before 1900, and showed that the remains of early pioneers still lie beneath the park, while much of the log church destroyed by fire in 1836 remains beneath St. Ferdinand Street. Florissant also preserved a rich architectural heritage through a 1971 historic preservation ordinance and landmarks including the 1878 Narrow Gauge Railroad Station, later converted to an electric line and moved and restored in 1969, Casa Alvarez built in 1790 for Eugenio Alvarez, the circa 1850 Auguste Archambault House, the circa 1885 Mercantile Building of Henry and August Albers, and the circa 1858 Franz Gittemeier House, which community support helped save from demolition after Shell Oil Company purchased it in 1990.