One notable exception to Napoleon's strategy of annihilation and a precursor to trench warfare were the Lines of Torres Vedras during the Peninsular War. French Armies lived off the land and when they were confronted by a line of fortifications which they could not out flank, they were unable to continue the advance and were forced to retreat once they had consumed all the provisions of the region in front of the lines.
One notable exception to Napoleon's strategy of annihilation and a precursor to trench warfare were the Lines of Torres Vedras during the Peninsular War. French Armies lived off the land and when they were confronted by a line of fortifications which they could not out flank they were unable to continue the advance and were forced to retreat once they had consumed all the provisions of the region in front of the lines