This Osprey title examines the crucial campaign culminating in the hard-fought battle that finally drove the French from Portugal during the Napoleonic Wars (1799-1815). In October 1810 the Allied position in Portugal appeared precarious. Despite defeating Marshal Masséna's French army at Bussaco, Wellington had been forced to retreat to within a few miles of Lisbon. Here the French encountered a massive line of fortifications stretching from the River Tagus to the sea. Built amid great secrecy and on Wellington's specific orders, these Lines of Torres Vedras were the French high-water mark. In February, with his army on the point of starvation, Masséna was forced to retreat and the scene was set for the climactic action of Fuentes de Oñoro.