The Spanish Conspiracy of the mid-1780s arose in the aftermath of the American Revolution when the leaders of the Cumberland settlements, which were then still part of North Carolina, courted a possible relationship with the Spanish government in New Orleans. Following the Revolution, Spain attempted to arrest the increasing flow of Americans to the West by assisting the Creeks under the leadership of the mixed-blood Alexander McGillivray in their attacks on the Cumberland settlements. In addition, the Spanish controlled the Mississippi River and New Orleans. Although the Cumberland settlers were not yet producing goods that required a market outlet like New Orleans, they recognized the potential for commercial enterprises and looked to the Mississippi River as the future outlet for their trade. Spain, however, forbade American access to the river, and the North Carolina government in the east did not support the westerners in their demands for navigation rights.
Cut off from any legal outlet for trade and harassed by the Creeks, the western settlements became vulnerable to the possibility of breaking ties with the east to formulate a separate alliance with Spain or form a separate state under Spanish authority. Either option offered them access to a market for western goods and promised relief from Creek attacks. Such an alliance would provide the Spanish government in New Orleans with a buffer between Spanish-held territory and the newly formed United States.
James Robertson contacted the Spanish governor in New Orleans, Esteban Miro, concerning a plan for the western settlements to separate and join Spain. Dr. James White, serving as Indian agent, also contacted Miro, assuring him that the western settlers were prepared to set up an independent state with Spain.
Spain proposed that the westerners break relations with the United States and take an oath of allegiance to His Catholic Majesty, King of Spain. In return, the frontiersmen would be allowed access to the Mississippi and the right to manage their local affairs. Economic relations were soon established between Spain and the settlements. All trade traveling down the Mississippi to New Orleans was subject to a 15 percent duty and anyone who conducted business in Spanish territory had to sign the oath of allegiance. Those who chose to reside in Spanish Louisiana were promised large land grants, the right to practice the Protestant religion, and the same commercial rights as all Spanish subjects. Many westerners, including Andrew Jackson, took advantage of the opportunity and signed an oath in order to trade down the Mississippi.
The Spanish Conspiracy in Tennessee came to an end when North Carolina ratified the constitution of 1789. The cession of western territory to Congress satisfied the leaders of the Tennessee settlements, who now enjoyed the protection of the United States government. In 1795, amid mounting European hostilities, Spain agreed to surrender the Louisiana territory east of the Mississippi above the thirty-first parallel to the United States, restrain the southern Indian tribes under Spanish influence, and grant the United States free navigation of the Mississippi River with the right of deposit at New Orleans.