The plan of Bonaparte was to conduct thirty-five thousand men of the Army of Reserve over this pass into Italy, and to send the remaining five thousand over the Little St. Bernard Pass, which lies in the Alps but a few miles south of the Great St. Bernard. At the same time a small detachment was to proceed from Switzerland into Italy by way of the Simplon Pass; and Thurreau's division of four thousand, which formed the left of the Army of Italy, was to descend from the Mont Cenis Pass and attack the Austrians in the vicinity of Turin. These movements having been accomplished, Bonaparte intended to direct the greater part of the Army of Reserve on Milan, where it was to unite with Moncey's corps, which was marching over the St. Gothard into Italy. Should this part of the plan be successfully executed, Bonaparte then purposed to march south with a strong force, cross the Po near Placentia, and occupy the Stradella Pass. This pass, which is enclosed on the north by the Po and on the south by the spurs that shoot northward from the main chain of the Apennines, is a strong position on the direct road between Alessandria and Mantua. While holding the pass, Bonaparte expected to debouch westward therefrom against Melas, who, he calculated, would advance eastward from Alessandria and meet him in the plains of the Scrivia. It is clear, from the histories of this campaign, that the plan as here set forth had not been determined on in all its details before the movements began. In fact, until Bonaparte descended the eastern slope of the Alps, he had not fully decided whether he would march directly on Milan, or on Alessandria and the fortress of Tortona, in order thus to bring relief more quickly to Masséna. Circumstances would then determine the matter. But there is little doubt that before leaving Paris he had mapped out in his own mind the essential features of the plan as here set forth. Upon this point Bourrienne, in his "Memoirs of Napoleon Bonaparte," writes as follows:--