Shortly after, two new divisions of National Guardsmen were formed in Angers and Niort, where they were joined by 1,000 gendarmes to help police the countryside.

[4][5] During the Vendéen Revolt, the corps consisted of two divisions, and after 11 June was expanded by 3,000 men, and by the 17th the corps was expanded into the 'Army of the West' (Armée d'Ouest), though also known as the Army of the Vendee (Armée de la Vendée) consisting of 6,000 men.

A 'Corps of Observation' doesn't have any modern equivalent, but during the Napoleonic Wars these Corps were used by the Imperial Army many times.

The purpose of these corps, throughout the war, was to provide a modern equivalent of border reconnaissance, reporting back to reserve units on enemy movements.

These corps could then quickly move and mobilise local units to provide a rearguard till further reinforcements could arrive.