The Army of the Pyrenees was formed on 1 October 1792 and a former Minister of War, Joseph Marie Servan de Gerbey was appointed to lead it.
The War of the Pyrenees between Republican France and the Kingdom of Spain began on 9 March 1793.
Accordingly, the original Army of the Pyrenees was split on 30 April into the Army of the Western Pyrenees with Servan in command and the Army of the Eastern Pyrenees.
Servan's new army covered a front from the Garonne River in the Pyrenees to the Bay of Biscay, then up the coast to the Gironde estuary.
 Historian Ramsay Weston Phipps called the Army of the Western Pyrenees the "least interesting" of the armies of the French Republic, contributing only one future marshal.
On 19 May 1804, Napoleon elevated Bon-Adrien Jeannot de Moncey to the rank of marshal.

An order of battle for 1793 listed two battalions each of the 20th, 80th, and 148th Line Infantry Demi-brigades and the 5th Light Infantry Battalion.
In addition to 18 free companies, there were the following National Guard infantry battalions, Aldudes, 3rd Dordogne, 3rd Landes, 4th Lot-et-Garonne and Paris Louvre.
The cavalry regiments were the 18th Dragoons, Volunteers of the Western Pyrenees (later the 12th Hussars) and Bayonne Volunteer Chasseurs (later the 24th Chasseurs à Cheval).
There were also 15 artillery companies.
In March 1793, Servan had about 10,000 troops at his disposal.
At first the volunteer battalions averaged only about 200 men apiece, but in May 1793 they were all recruited up to strengths of 784 soldiers.

The first amalgame began in 1793 and by 5 September five demi-brigades were created with a nominal strength of 2,437 men and divided into three battalions of 812 soldiers.
Eventually, 18 more demi-brigades were formed, giving the army a total of 60,000 men.
Of these, probably one-third served in garrisons and were of lower quality.
Because it was difficult to procure forage, the cavalry was perpetually understrength and about two-thirds of the horses died during the course of the war.
Fortunately, the terrain did not lend itself to operations by mounted troops.
Military transport and the artillery also suffered from the problem of inadequate forage and never had enough horses.
The artillery arm was built up from scratch into a considerable force thanks largely to the capture of 535 Spanish guns and the efforts of the army's artillery chief Augustin de Lespinasse.
He also created a pontoon train and units of artisans who repaired muskets taken from the Spaniards.
Another innovation of the Army of the Western Pyrenees was its organization of work companies.
While the army's soldiers initially suffered due to lack of supplies, by the end of the war the troops were well equipped by their logistical base at Bayonne.

Because Servan was associated with Jean-Marie Roland, vicomte de la Platière of the fallen Girondist faction, he was dismissed on 4 July 1793.
Servan was temporarily replaced by Anne François Augustin de La Bourdonnaye until 11 July when Pierre Joseph du Chambge d'Elbecq arrived to take command.
La Bourdonnaye took command of the right wing but he died at Dax on 7 October 1793.
D'Elbecq died on 31 August 1793 at Saint-Jean-de-Luz, having accomplished very little.
He was succeeded by Étienne Deprez-Crassier who irritated the representatives-on-mission.
Deprez-Crassier was dismissed on 4 October and arrested four days after.
The following day, Jacques Léonard Muller was named the army's commander-in-chief.
Muller had been appointed the army's chief of staff and promoted to general of brigade on 5 July 1793.
As general of brigade he was junior to ten generals of division but he was the choice of the all-powerful representatives-on-mission.
On 8 September 1793 the Minister of War sent Thomas-Alexandre Dumas to take command of the army and promoted several officers to general of brigade.
The representatives refused to recognize Dumas' authority or the promotions.
In the end they won and Dumas was merely recognized as a division commander.

In July 1793 Army of the Western Pyrenees numbered 28,000 infantry, 1,5
The Army of the Pyrenees was formed on 1 October 1792 and a former Minister of War, Joseph Marie Servan de Gerbey was appointed to lead it. The War of the Pyrenees between Republican France and the Kingdom of Spain began on 9 March 1793. Accordingly, the original Army of the Pyrenees was split on 30 April into the Army of the Western Pyrenees with Servan in command and the Army of the Eastern Pyrenees. Servan's new army covered a front from the Garonne River in the Pyrenees to the Bay of Biscay, then up the coast to the Gironde estuary.  Historian Ramsay Weston Phipps called the Army of the Western Pyrenees the "least interesting" of the armies of the French Republic, contributing only one future marshal. On 19 May 1804, Napoleon elevated Bon-Adrien Jeannot de Moncey to the rank of marshal.
An order of battle for 1793 listed two battalions each of the 20th, 80th, and 148th Line Infantry Demi-brigades and the 5th Light Infantry Battalion. In addition to 18 free companies, there were the following National Guard infantry battalions, Aldudes, 3rd Dordogne, 3rd Landes, 4th Lot-et-Garonne and Paris Louvre. The cavalry regiments were the 18th Dragoons, Volunteers of the Western Pyrenees (later the 12th Hussars) and Bayonne Volunteer Chasseurs (later the 24th Chasseurs à Cheval). There were also 15 artillery companies. In March 1793, Servan had about 10,000 troops at his disposal. At first the volunteer battalions averaged only about 200 men apiece, but in May 1793 they were all recruited up to strengths of 784 soldiers.
The first amalgame began in 1793 and by 5 September five demi-brigades were created with a nominal strength of 2,437 men and divided into three battalions of 812 soldiers. Eventually, 18 more demi-brigades were formed, giving the army a total of 60,000 men. Of these, probably one-third served in garrisons and were of lower quality. Because it was difficult to procure forage, the cavalry was perpetually understrength and about two-thirds of the horses died during the course of the war. Fortunately, the terrain did not lend itself to operations by mounted troops. Military transport and the artillery also suffered from the problem of inadequate forage and never had enough horses. The artillery arm was built up from scratch into a considerable force thanks largely to the capture of 535 Spanish guns and the efforts of the army's artillery chief Augustin de Lespinasse. He also created a pontoon train and units of artisans who repaired muskets taken from the Spaniards. Another innovation of the Army of the Western Pyrenees was its organization of work companies. While the army's soldiers initially suffered due to lack of supplies, by the end of the war the troops were well equipped by their logistical base at Bayonne.
Because Servan was associated with Jean-Marie Roland, vicomte de la Platière of the fallen Girondist faction, he was dismissed on 4 July 1793. Servan was temporarily replaced by Anne François Augustin de La Bourdonnaye until 11 July when Pierre Joseph du Chambge d'Elbecq arrived to take command. La Bourdonnaye took command of the right wing but he died at Dax on 7 October 1793. D'Elbecq died on 31 August 1793 at Saint-Jean-de-Luz, having accomplished very little. He was succeeded by Étienne Deprez-Crassier who irritated the representatives-on-mission. Deprez-Crassier was dismissed on 4 October and arrested four days after. The following day, Jacques Léonard Muller was named the army's commander-in-chief. Muller had been appointed the army's chief of staff and promoted to general of brigade on 5 July 1793. As general of brigade he was junior to ten generals of division but he was the choice of the all-powerful representatives-on-mission. On 8 September 1793 the Minister of War sent Thomas-Alexandre Dumas to take command of the army and promoted several officers to general of brigade. The representatives refused to recognize Dumas' authority or the promotions. In the end they won and Dumas was merely recognized as a division commander.
In July 1793 Army of the Western Pyrenees numbered 28,000 infantry, 1,5
Army of the Western Pyrenees