For fifty years, through the second half of the seventeenth century, the armies of France were the most powerful and most admired in Europe. Its forces were overwhelmingly the largest on the continent. In peacetime, it kept a standing army of 150,000, and expanded this to 400,000 in time of war. During the War of the Spanish Succession, eight large French armies, each commanded by a marshal of France, campaigned simultaneously in the Low Countries, on the Rhine, in Italy and in Spain. Thanks to the King and Louvois, France's soldiers were the best trained, the best equipped and the best supplied in Europe. Thanks to generals such as Turenne, Cond6 and Vendome, they were overall also the most successful. The Duke of Marlborough's shattering defeat of Marshal Tallard at Blenheim (the Duke was aided by his companion-in-arms, Prince Eugene of Savoy) was the first great defeat of the French army since the Middle Ages.
Throughout this period, the size, firepower and destructiveness of all armies was growing rapidly. As energetic finance ministers enlarged the tax base for the support of armies, increasing numbers of troops could be put into the field. In the first half of the seventeenth century, a European battle might see as few as 25,000 troops involved on both sides. In 1644, at Marston Moor, the decisive battle of the English Civil War, Cromwell pitted 8,000 men against an equal number under King Charles I. Sixty-five years later, at Malplaquet, Marlborough led 110,000 allied troops against 80,000 Frenchmen. At the peak of its strength, Sweden, with a home population of a million and a half, supported an army of 110,000. Peter, even after dismissing the disorganized, irregular mass of feudal soldiery he inherited from Sophia and Golitsyn, eventually raised and trained a completely new army of 220,000.
Although, as wars dragged on, conscription became necessary to fill the ranks, most armies in this period were made up of professional soldiers. Many of these, both officers and men, were foreign mercenaries—in that time, a soldier could join any army he liked as long as he did not fight against his own king. Frequently, kings and princes who were at peace rented out whole regiments to warring neighbors. Thus, Swiss, Scots and Irish regiments served in the French army; Danish and Prussian regiments in the Dutch army; and the Hapsburg Imperial army contained men from all the German states. Individual officers changed sides as often as modern executives change jobs, nor did their past or future employers bear them ill-will for their actions. As a twenty-four-year-old colonel, Marlborough served under Marshal Turenne against the Dutch and was personally praised at a great parade by Louis XIV himself. Later, in command of a predominantly Dutch army, Marlborough almost toppled the Sun King from his throne. For a while, both before and after Peter came to the throne, most of the senior officers in the Russian army were foreigners; without them, the Tsar could have fielded little more than a mob.
Customarily, these professional soldiers conducted warfare by accepted rules. There was a seasonal rhythm to war which was rarely broken: summer and autumn were for campaigning and battles; winter and spring were for rest, recruiting and replenishment. In the main, these rules were dictated by the weather, the crops and the state of the roads. Every year, the armies waited until the spring thaw had melted the snows and enough fresh green grass had sprouted to nourish the horses of the cavalry and baggage trains. In May and June, once the mud had dried to dust, long columns of men and wagons began to move. The generals had until October to maneuver, besiege and offer battle; by November, when the first frost appeared, the armies began going into winter quarters. These rules were almost religiously observed in Western Europe. Through ten consecutive years of campaigning on the continent, Marlborough regularly left the army in November and returned to London until spring. In the same months, senior French officers returned to Paris or Versailles. A long-vanished aspect of those civilized wars was the issuance of passports to prominent officers to travel through hostile territory on the shortest routes for winter leave. Common soldiers, of course, did not enjoy these priviliges. There was no question of home leave for them until the war was over. If they were fortunate, they were confined to billets in town through the coldest months. All too often, however, they were crowded into winter encampments of huts and hovels, prey to frostbite, disease and hunger. In the spring, the gaps chewed through their ranks by pestilence would be filled by fresh consignments of recruits.
On the march, an army of .this period moved slowly, even when its passage was unopposed; few armies could move faster than ten miles a day, while the average daily march was five. Marlborough's historic march from the Low Countries up the Rhine to Bavaria before the Battle of Blenheim was considered a "lightning stroke" at the time—250 miles in five weeks. The limiting factor usually was the artillery. The horses struggling to pull the cumbersome, heavy cannon, whose wheels fearsomely rutted the roads for those that followed, simply could not move faster.
Armies marched in long columns, battalion after battalion, a screen of cavalry riding in front and on the flanks, the carts, carriages and gun caissons trundling along in the rear. Normally, an army marched at sunrise and camped in mid-afternoon. Making a new camp every night required almost as much effort as the day's march. Tents were erected in lines, baggage unpacked, cooking fires lit, water provided for men and animals, and the horses set to grazing. If the enemy was nearby, each camp had to be placed on suitable ground and prepared with temporary earthworks and wooden palisades as a potential strongpoint able to resist attack. Then, after an exhausted sleep, the men were roused, and in the pre-dawn darkness all this had to be dismantled and packed into wagons for the next day's march.
Not everything, of course, could be carried in wagons. An army of 50,000 to 100,000 men could maintain itself only by marching through fertile countryside which could supply many of its wants, or by having additional supplies brought to it by water. In Western Europe, the great rivers were the railways of war. In Russia, where the rivers flow north and south and the war between Russia and Sweden was east-west, rivers were of little value, and the consequent dependence on wagon trains and local foraging was far greater.
In Western Europe, most campaigns proceeded in a leisurely manner. Sieges were popular and much preferred to the greater risks and nasty surprises of open-field battle. Siege warfare was conducted with exquisite, almost mathematical precision; on each side, at any given moment the commander knew exactly where matters stood and what was going to happen next. Louis XIV was devoted to siege warfare; there was no risk of losing the great army which he had so carefully and expensively built. Also, it enabled him to participate safely in the Game of Mars. Besides, in Louis de Vauban, the Sun King possessed the greatest master of fortification and siege operations in the history of warfare. On behalf of his master, Vauban personally laid siege to fifty towns without failure, and his own fortresses were the models for the age. Sometimes purely military bastions, sometimes large fortified towns or cities, they covered and protected the frontiers of France like an interlocking web. Carefully adapted to the particular terrain, each was a work not only of supreme utility but also of art. They tended to be shaped like a gigantic star, with each rampart built so as to be protected by flanking enfilade fire from cannon or at least musketry at right angles. Each salient was a self-contained fort, with its own artillery and garrison, its own sally ports for sudden sorties by the defenders. Around these great stone ramparts ran a tracery of ditches, twenty feet deep and forty feet wide, also faced with stone—bleak and desolate places for attacking infantry to find itself. When they were built, France's armies were on the offensive, and these fortresses, their great doors decorated with gilt fleur-de-lis and opening onto buildings of severe splendor, were intended not as static defense points but as pivots on which French armies could maneuver. Later, as Marlborough's armies were battering their way toward Paris and Versailles, Vauban's fortresses saved the Sun King his throne.