Napoleon was not a great innovator but imposed his genius and personal leadership on the huge, largely conscript armies he inherited from the Revolution. He perfected their offensive, mobile and ruthless way of war, but though he often wrote and talked about the so-called principles of war he never enumerated them or wrote a comprehensive account of his own ideas.

Essentially he was a pragmatist, explaining that in war ‘there are no precise or definite rules’ and that ‘the art of war is simple, everything is a matter of execution’. Even so, it is possible to deduce some constant elements from his campaigns, many already evident in Ital~ Napoleon was convinced that unity of command was essential. ‘In war,’ he informed the Directoire, ‘one bad general is better than two good ones.’ He always fought offensively even when on the strategic defence – the destruction of the enemy’s main field army, rather than the occupation of territory or the enemy’s capital, his primary objective.

Strategic deployments were planned carefully. Even before hostilities opened efforts were made to shroud the emperor’s intention. Newspapers were censored, borders closed, travellers detained. Swarms of light cavalry screened the army’s advance and gathered intelligence about the location of the enemy. The self-contained corps marched along separate but parallel routes, deployed to cover the entire area of operations. When the main enemy body was located, Napoleon would close up deployment to bring his corps within supporting distance, adopting a loosely quadrilateral formation known as the bataillon carre. The first corps to contact the enemy would engage to pin him, while the others would hurry to its support. When concentration had been achieved Napoleon often disposed of superior numbers, but if this proved impossible he manoeuvred to gain local superiority at the decisive point. Still, several of his battles were won only by the fortuitous arrival of detached forces.

Success depended on tight security, good intelligence, precise staff work and, above all, great marching feats. Of these, the last two were difficult to achieve. In round numbers, 30,000 marching infantry required 8 kilometres of good road; 60 guns with their caissons took up 4 kilometres, and 6,000 cavalry, riding four abreast, needed about 7 kilometres. And strategic approach marches were long. In September-October 1805 several corps marched up to 300 kilometres in ten days; and in December Davout’s corps, urgently summoned to Austerlitz, covered over 100 kilometres in two days; with an ample road network the bataillon carre formation was capable of rapid, large-scale movements.

In battle, as in his strategic approach, Napoleon always favoured the offensive. In all of his battles he stood only three times on the defensive at Leipzig in 1813, and at La Rothiere and Arcis in 1814 – and each time only after his initial attack had failed. Napoleon’s battle plans – grand tactics – were similar to his strategic pattern. There were three major variants: the central position, the flanking envelopment and the frontal attack. The first he used when the enemy outnumbered his troops. He would seize the initiative, taking up a central position to divide the hostile forces. Then, while a portion of his troops engaged one part of the enemy force, he turned his main body against the other and defeated it. Finally, the main force would join the pinning force against the second opponent. In his second variant the flanking attack sometimes expanded into a full-scale envelopment, and involved one part of his army engaging the enemy front while a sudden attack crushed one of the flanks. If an envelopment was feasible there would be a holding action pinning the enemy, while the bulk of the army swept around him in forced marches – the famed manoeuvre sur les derrieres – which compelled him either to surrender or to give battle with no satisfactory line of retreat. Finally, if time, terrain or the opponent’s dispositions made either of these approaches impossible, there was the frontal attack, weakening the centre by threatening the flanks, and then launching the breakthrough force, the masse de rupture. Such attacks, however, required the use of combined arms, infantry, cavalry and artillery operating together with careful timing; they were costly and rarely successful.

A large part of Napoleon’s success depended on his ability to inspire his subordinate commanders and his men. Courage and resolution were essential qualities for a general. Seniority counted for little and intellect alone even less. As he once said, ‘I cannot abide promoting desk officers; I only like officers who make war.’ If bravery and success were essential, favour also played a role, and he always retained a special regard for those who had served with him in Italy and Egypt.

Napoleon believed that personal leadership, coupled with appeals to pride, inspired men to fight, maintaining that ‘the morale and opinion of the army are more than half the battle’. He understood that it was not, in the long run, the ideals of the nation, or of the Republic or the Revolution that motivated men. It was the army’s romance of itself, expressed by symbols and legends. ‘The military,’ he is reported to have said, ‘is a freemasonry and I am its Grand Master’; he reinforced these feelings both by personal rewards and recognition of corporate achievement. His personal charisma and his carefully fostered relations with his troops were most effective, even when luck had deserted him. Wellington believed that Napoleon’s presence in battle was worth two corps.