He joined the French Royal Army and served in an infantry regiment during the American Revolutionary War before retiring to his estates in 1780.

[2] Upon the outbreak of the War in the Vendée, the local Vendeans offered to make Royrand their leader but he was reluctant to accept at first.

He proved to be a capable organizer while assigning his second-in-command Charles Sapinaud de La Rairie to lead the rebels in the field.

While Canclaux held Angers, Nantes and the west coast department of Loire-Inférieure, Biron was responsible for Les Sables-d'Olonne, Luçon, Fontenay-le-Comte, Niort and Saumur.

[5] The National Convention rushed reinforcements to the scene including 12 poorly-disciplined volunteer battalions from Paris under Antoine Joseph Santerre.

[6] In May 1793, while Royrand's army watched the southern edge of the Vendée, the rebels seized Bressuire and Thouars in the east.

[7] This was followed by a rebel victory over Jacques-François Menou's division at the Battle of Saumur on 9 June in which the Vendeans captured 46 cannons.

Ignoring Biron's wishes, 12,000 men of the Saumur division under Jacques-Marie Pilote La Barolière moved west.

Because François Séverin Marceau-Desgraviers carried out an effective reconnaissance, Tuncq was aware that the rebels were massing for a big attack.

On 14 August 1793, in the Battle of Luçon, 14,000–35,000 Vendeans mounted an assault with Charette and Lescure on the right, Elbée and Royrand in the center and La Rochejaquelein on the left.

At first, Charette and Lescure's men pushed back the Republican left flank and overran five guns, but the attacks were poorly timed and the column of Elbée and Royrand came up too late.

[14] Tuncq sent 7,000 soldiers under René François Lecomte and Marceau north to occupy Chantonnay in an exposed position.

Soon 14,000 veteran soldiers of the so-called Army of Mainz under Jean-Baptiste Annibal Aubert du Bayet were on the march for the Vendée.

The Republican generals and representatives agreed to mount a converging attack on the Vendée with the main thrust coming from Nantes.

While trying to contact the main army's advance guard under Michel de Beaupuy, the Luçon Division was ambushed in the Battle of La Tremblaye on 15 October.

[23] The Republicans occupied Cholet on 16 October and Jean Baptiste Kléber prepared to defend the town from rebel attack.

[24] The Vendean army crossed to the north bank of the Loire at Saint-Florent-le-Vieil while the Republican soldiers celebrated their victory by running amok in Cholet and Beaupréau.

[25] The Catholic and Royal Army, numbering 50,000, including 30,000–35,000 fighting men, elected La Rochjaquelein as their leader.

[27] After passing through Château-Gontier on 25 October, the Republican advance guard under Westermann blundered into a Vendean ambush south of Laval and was driven back.

Kléber soon brought his division into the fight, but with the army strung out on a single road it proved difficult for the Republicans to get more troops into action.

[29] Led by La Rochejaquelein and Royrand in the center, the Vendeans forced back the Republicans, turning captured cannon against their former owners.

In the Battle of Entrames on 26 October the Vendeans dispersed the Army of the West inflicting very heavy losses and capturing 19 cannons.

When the revolt broke out, the Vendeans asked Charles Augustin to lead them and he was killed in the fighting at La Guérinière on 19 March 1793.