The war began when France lost the Fourth Intercontinental War and was forced to give Louisiana to Spain. The Louisianans were unhappy with the change in leadership and the whole nation was moved to fight the superior Spanish military. Spain could fight a conventional war, but it could not fight a war against over a million people working together against them, especially since the military involved was strictly colonial.
El Dorado Campaign
War broke out on April 2, 1763 when Spanish soldiers marched into southeast Louisiana to occupy the new territory. With the generals from the Fourth Intercontinental War still not returning to the most urban area of the territory, the Louisianans were left to fend for themselves. They retrieved weapons from their factories and stockpiles and began ambushing Spanish soldiers in El Dorado. The Spanish commanding officer, Charles II was killed in the attack, and the Spanish struggled to organize themselves as word was sent to other commanders on both sides. The Louisianan makeshift army then marched south toward Shreveport on August 4, where they engaged the Spanish and pushed them back against a large river that ran through the city.
The New Spanish were in danger of being split between New Orleans and northern areas, so they moved to capture Alexandria on November 12, splitting up the forces of the Louisianans. The ones trapped in the south were captured or killed. Finally, on January 8, 1764, Chevalier de Lévis reached the northern front after recovering from the small pox north at Saint-Pierre. He led the Louisianans to a second victory at El Dorado and then moved southeast to Winnfield where he completed the "semi-encirclement" of the New Spanish remaining in Many and De Ridder. On July 17, he moved against the latter, dislodging the Spanish from their placements there and paved the way for an invasion from the north, which came on August 5. Once the city was won, forces converged on Many from three directions, fully removing the Spanish from the western half of the nation. Within a few weeks, the majority of these victories had been reversed, however, and things looked grim for Louisiana when de Lévis had to leave for almost 4 years to fight the Rocky Mountain campaign
The Rocky Mountain Campaign
Word reached de Lévis on March 6, 1765 of an attack in the Rocky Mountains. He decided he would have to abandon the south for now, as he had no fellow generals to send north. When he reached the Rockies, he found that the Spanish were moving through Pikes Peak, and his men had to scale the mountain while engaging the Spanish. The Battle of Pikes Peak lasted 2 years and claimed thousands of lives.
Next, with his tattered forces, de Lévis was forced to cut off a second advance at Longs Peak even farther to the north. This battle went similarly to the first, and de Lévis was able to chase the Spanish down the mountain after heavy losses and over a year. The bulk of Louisianan losses came from this battle due to the disastrous opening move by de Lévis to attempt to climb to the peak from multiple directions to defeat the Spanish quickly. This decision led to a hailstorm of musket fire onto Louisianan forces and a smaller volume of targets for individual Spanish stations along the mountainsides. In fact, it was seen as a miracle that de Lévis was not only able to salvage the situation, but go on undefeated from this point on in the war. By the time the Spanish had been weakened enough that the Louisianans could advance to the peak and capture the area, 20,000 Louisianans had been killed.
The Gulf Campaign
Finally, the Spanish were on the verge of being pushed out of Louisiana for good and the world was shocked at what was happening, but the numbers of the colonist army were dwindling. De Lévis was hoping the citizens of the few cities left to be liberated would join the army or at least work toward the goal of defeating New Spain. It turned out that this was true, and when his diminished force of around 2,000 reached Alexandria on November 24, 1769, they were greeted by cheering citizens who attacked the Spanish forces. The battle was taxing on the army itself though, diminising its numbers by a third.
When the city was taken, Chevalier decided that a decisive blow at Baton Rouge or Lafayette would drive the Spanish out for good. He raised an army of 3,000 from the citizens of Alexandria and attacked Lafayette on March 4, 1770. The ragtag band of colonists was barely able to defeat the Spanish, but they eventually did after a 3 day battle that came down to a total of 900 soldiers on each side by the end. The Spanish were no longer in Louisianan territory at this point, but just to deal a final blow, de Lévis forced the captured soldiers to assist him in his journey to the large New Spanish town of Cortez to defeat Spain on its own territory.
End of the War
The Battle of Cortez occurred on August 9, and was a decisive Louisianan victory against all odds. The small troop of Louisianans surrounded the city and captured the army there, dealing a blow to Spain on its own soil for the first time. After this battle, the Spanish were forced to accept the Treaty of New Orleans and recognize Louisiana as a free nation. Chevalier was hailed as a war hero and retired to his quarters at Sainte-Pierre, later coming out of retirement to train soldiers for the nation and appoint commanders to take his place.