The Peninsular War had started in Portugal with the Invasion of Portugal (1807) and went on till 1814. In September 1810 Masséna made the third French attempt to occupy Portugal with his 65,000 strong army fighting in the Battle of Bussaco, but Wellington pulled back his army southwards. The French army under Masséna pursued Wellington and discovered a barren land without inhabitants, as the Portuguese peasants had left their farms after destroying all food they could not take with them and anything else that might be useful to the French as required by the scorched earth policy. On 11 October 1810, Massena with 61,000 men found Wellington behind an almost impenetrable defensive position, the Lines of Torres Vedras consisting of forts and other military defences built in absolute secrecy to defend the only path to Lisbon from the north. The lack of food and fodder meant that Masséna was forced to retreat northwards, starting on the night of 14/15 November 1810, to find an area that had not been subjected to the scorched earth policy. The French held out through February although the Iberian peninsula had suffered one of the coldest winters it had ever known, but when starvation and diseases really set in, Masséna ordered a retreat at the beginning of March 1811 having lost another 21,000 men.