The battalion arrived at Quebec on 19 June and, after a brief rest, was dispatched with the Guyenne battalion to garrison Fort Frontenac. At the end of autumn it withdrew to winter quarters.

Montcalm succeeded Dieskau as commander of the French forces in May 1756. He quickly moved to Ticonderoga with several regular battalions to block a possible British move against the position. The battalions of the Guyenne and La Sarre were sent to Fort Frontenac. The Bearn battalion was ordered to Niagara, but was recalled at the end of July and sent by boat to reinforce the garrison at Fort Frontenac.

As the British threat failed to materialize, Vaudreuil and Montcalm planned a strike against Oswego, a British post established in the 1720s at the eastern end of the south shore of Lake Ontario. Oswego was intended to attract the fur trade of the western Indians, but it also provided a British base from which to strike at forts Frontenac and Niagara. Montcalm's aim was to eliminate the enemy foothold on Lake Ontario and to secure the western frontier of New France,

The Oswego position was composed of three fortified posts. Fort Ontario, a recently built star-shaped log fort, was located on high ground on the east side of the Oswego River. On the west bank stood the original Fort Oswego, surrounded by a stone wall and protected to the south and west by earthworks, but exposed to the east. The third post was a fortified cattle pen 1.5km (1 mi.) upstream from the main defences. The series of fortifications was garrisoned by about a thousand men under the command of Colonel Mercer.

Montcalm swiftly assembled his strike force at Niaoure Bay on 8 August. The battalions of the Beam, La Sarre, and Guyenne regiments, together with several companies of colonial regulars, militia, and Indians, brought the force to 3,000 men.

Moving at night, the force approached Oswego without being detected by the British, and by 10 August it was in position to attack the fortifications. Led by Captain Pouchot of the regiment de Bearn, the initial advance pressed forward while parallels and batteries were constructed to face the forts. The wooden ramparts of Fort Ontario were useless against the French guns, and the garrison retreated across the river to Fort Oswego. The French occupied the Ontario site dominating Old Fort Oswego, and swept the exposed British position with a fierce bombardment. Mercer was killed, and the garrison surrendered on 14 August.

Montcalm burned the forts, sent his prisoners and captured supplies to Montreal, and hastened his troops back to Ticonderoga before the British learned of the events.

Although Oswego was not a major fortress, its capture and destruction had an immediate effect, for the British were there-after reduced to using only one inland approach, the Lake Champlain waterway.

The speed and power of the French attack greatly impressed the Indians as well as the British, and French prestige soared as that of the British sank. Furthermore, the Oswego operation demonstrated the value of properly employed regular soldiers even in the Canadian wilderness. As even stout wooden palisades were easy prey for soldiers trained in siege craft, the arrival of French and British regulars changed the character of the war. Battles, not raids and war-parties, would decide the fate of Canada.

The regiment de Bearn accompanied Montcalm to Fort William Henry in 1757. The following year it took part in the defence of Ticonderoga, where, with the Guyenne and La Sarre regiments, the Beam formed the right flank of the French perimeter. It was against this sector of the French position that the Black Watch launched its impetuous attack.

At the beginning of the 1759 campaign, the Bearn battalion was assigned to the main force defending Quebec. When Montcalm marshalled his small army on the Plains of Abraham, the battalion of the regiment de Beam 'was in the centre of the line of battle.

Uniform

Illustrations of French regulars in Canada usually depict the justacorps with regimental distinctions as prescribed for European service. However, a special uniform was made in France to Ministry of the Navy specifications, and issued to the first troops to arrive in Canada As these coats were collarless, the battalions that came to Canada with Dieskau in 1755 could not be identified by the usual system of distinctive collar colour.

The uniforms issued to some regiments differed from their standard dress in other details as well. The European uniform of the regiment de Beam was distinguished by its red collar, red cuffs with three buttons along the edge, red waistcoat, brass buttons, and gold lace. The special Canadian issue for the regiment, however, had blue cuffs and waistcoat, pewter buttons, and silver lace.

By 1758, the original battalions were no longer supplied with the special Canadian pattern of clothing; all the French regulars were clothed in European dress, complete with prescribed regimental distinctions.

In 1755, the dress of the regiment de Beam consisted of the traditional greyish-white justaucorps with deep cuffs of blue, but without the usual small collar. The skirt, which reached the top of the knee, could be hooked up for greater freedom of movement, or allowed to fall straight for ceremonial occasions or to give additional protection to the legs in inclement weather. The Beam had a distinctive coat pocket, consisting of a three-pointed double vertical slash with a large button at each point. While this pocket design is clearly shown in the illustration, the artist's retention of regimental pocket distinctions in the Canadian-pattern uniform is purely speculative as documentary evidence is not available.

The greyish-white breeches were buttoned on the side and buckled below the knee. Black shoes with metal buckles were worn over white wool stockings. On campaign and parade, the soldiers wore white canvas gaiters that reached just to the bottom of the coat. These were fastened below the knee by a black leather strap.

All ranks wore the black felt tricorn with black or white cockade. The brim was edged with fake-silver tape for privates and corporals, and fine silver lace for sergeants and officers. Other items of dress included a black cravat and white linen shirt.

The officers' uniform was of the same colour and pattern as hat of the men, but of better material, and the waistcoat was often trimmed with gold or silver lace. A buff leather sword-belt went around the waist either over or under the waistcoat, but usually under the justaucorps. A white cravat, showing a lace frill at the throat, was worn with a white shirt. The gilt gorget denoting commissioned rank was always worn on duty.

In addition to a sword, captains and higher-ranking officers carried an espontoon; junior officers carried a fusil or musket with cartridge-box, as did the men.

The soldier shown in the plate is a corporal of the grenadier company, dressed in the Canadian Issue uniform of 1755. Though grenades were no longer used, grenadiers were still selected from among the biggest soldiers in the battalion. A French grenadier sported a distinctive moustache, although other soldiers were clean shaven. He wore a large grenade pouch with the King's Arms stamped on the flap, and carried a brass-hilted sabre instead of the usual straight-bladed short sword.

Three strips of braid on the cuff formed (he usual rank badge for corporals, although the particular pattern and arrangement of the strips differed from regiment to regiment.

The corporal is armed with a 1746 French military musket, and wears the standard infantry waist-belt with double frog for sabre and bayonet. His grenadier cartridge pouch is suspended on the right hip from a buff leather cross-belt.