The history of St. Louis, Missouri from 1763 to 1803 was marked by the transfer of French Louisiana to Spanish control, the founding of the city of St. Louis, its slow growth and role in the American Revolution under the rule of the Spanish, the transfer of the area to American control in the Louisiana Purchase, and its steady growth and prominence since then.
In mid-1763, French Governor Jean-Jacques Blaise d'Abbadie granted a trade monopoly over the west upper Mississippi region to Gilbert Antoine de St. Maxent, a New Orleans merchant. Maxent quickly engaged the service of Jean Francois Le Dee and Pierre Laclède to build trading posts in the Illinois Country. Fur trading was becoming a more lucrative profession and many more started to travel up the Mississippi River for the same reason. Shortly before the upriver departure of Laclède in August 1763, word arrived that France had ceded its territory on the east bank of the Mississippi to Great Britain according to the Treaty of Paris (1763), giving new significance to the trading posts on the west bank. The group led by Laclède included his young stepson Auguste Chouteau and roughly twenty boatmen with a cargo of trade merchandise.
On November 3, 1763, the group arrived at Ste. Genevieve and Fort de Chartres, where they stored their merchandise while preparing to build a new settlement farther north. They had to act quickly as the midwest brutal winter was setting in. In December, Laclède and Chouteau scouted potential locations on the west bank, with Laclède determining the suitability of a site with a gentle slope ending in a rocky bluff above the river's floodwaters. Laclède marked the area and instructed Chouteau to return in the spring to clear the land for construction. The men returned to Fort de Chartres for the winter to recruit workers, but in February, Laclède sent Chouteau and 30 men to begin construction of cabins and a shed for supplies. The settlement was established on February 15, 1764.
Laclède himself arrived in April 1763 to inspect the site, at which point he named the village St. Louis and provided detailed plans for laying out streets and for construction of his headquarters. The plan of the village was similar to that of New Orleans, including a public marketplace centered on the riverfront and a grid street pattern. The market, Laclède's headquarters, and a church stood in a line of blocks west from the bank of the river, and the market block was separated from the river by a limestone block ledge. Three streets ran parallel to the river: First Street (also known as La Rue Royale, La Grande Rue, and Main Street), Second Street (also known as La Rue d'Eglise or Church Street), and Third Street (also known as La Rue des Granges or Barn Street). North of the market block and perpendicular to the river was Market Street (also known as La Rue de la Place or La Rue Bonhomme); south of the market block were Walnut Street (also known as La Rue de la Tour) and Chestnut Street (also known as La Rue Missouri). In addition, many prominent, intelligent figures, such as Madame Marie-Therese Chouteau, had moved to St. Louis, and with their keen eye and intelligence, was able to advise the new residents on how to best prosper in the local government and home.