[4][5] Having occupied the heights of Bussaco, a 10-mile (16 km) long ridge located at 40°20'40"N, 8°20'15"W, with 25,000 British and the same number of Portuguese, Wellington was attacked five times successively by 65,000 French under Marshal André Masséna.

However, Wellington was ultimately forced to withdraw to the Lines of Torres Vedras after his positions were outflanked by Masséna's troops.

Using selective demolition of bridges and roads, Wellington restricted the choice of routes the French could use and slowed their advance.

The ridge, which at its highest rises to 549 metres (1,801 ft), lies at a right angle to the main road to Coimbra and thence to Lisbon, providing one of the few and certainly the best defensive position on the French route of march.

In batteries of six guns apiece, there were six British (Ross RHA, Bull RHA, Thompson, Lawson, two unknown), two King's German Legion (Rettberg, Cleeves) and five Portuguese (Rozierres, Da Cunha Preto, Da Silva, Freira, Sousa) batteries under Brig Gen Edward Howorth.

The divisions of Mag Gen Pierre Hugues Victoire Merle and MG Étienne Heudelet de Bierre made up Reynier's corps.

To improve his lateral communications, he had previously ordered his four officers from the Royal Corps of Engineers[9] to cut a road that ran the length of the ridge on the reverse slope.

When the leading regiment reached the top of the ridge, they found themselves facing the 74th Foot and two Portuguese battalions in line, plus 12 cannon.

"[15] Seeing Heudelet's second brigade standing immobile at the foot of the ridge, Reynier rode up to BG Maximilien Foy and demanded an immediate attack.

In this sector, the main highway climbed a long spur past the hamlets of Moura and Sula to reach the crest at the Convent of Bussaco.

As Loison's leading brigade approached the convent grounds, the two British units stood up, fired a terrific volley at point blank range and charged with the bayonet.

[15] The French brigade collapsed and fled, leaving BG Édouard Simon, their commander, wounded and a prisoner.

[12] A short time later and slightly further south, Loison's second brigade under BG Claude François Ferey ran into a close-range fire from two batteries plus Anglo-Portuguese musketry.

The French army was withdrawn towards Mortagoa, with fires lit in the woods to offer some camouflage to the troops' departure.

[17] Wellington, after spending the night in the convent, and finding his position turned, resumed the leisurely retreat of his army towards the, still being constructed, Lines of Torres Vedras.

Continuing to advance, Masséna had left his sick and wounded troops at Coimbra, where a few days later, they fell into the hands of the Portuguese.