To the Spaniards belongs the credit of having rendered the use of fire-arms more easy, more regular, and more general among the nations.  For more than a hundred years the Spaniards were the very masters of the art of war.  Their power had begun to decline, but they still retained their military superiority; and from the Battle of Ceresole, won by the Count of Enghien in 1544, down to the memorable victory of Rocroy, gained in 1643 by a hero of the same race and the same name, they had the upper-hand in all pitched engagements.  Their generals were the very best and most thoroughly instructed, and formed a real school; they, too, were the only officers who practised strategy.  Their organization was better than any other, and their celebrated tercios were the very model of all regiments.  Their armament was likewise superior, as they had adopted the musket, which was the first fire-arm that a man could handle with any facility, load with rapidity, and aim with any precision.  Each of their tercios or battalions contained a regulated proportion of these musketeers, and the number was large, compared to the whole mass of troops.

The excellent results attained by the Spaniards, in the more perfect organization and equipment of their infantry, did not escape the attention of the French officers; and one of them especially, the Duke Francis de Guise, endeavored to turn his observations to good account.  It is to him that we are indebted for the first rough sketch of regimental organization modelled upon that of the tercios, and, in more than one encounter with the Huguenots, the numbers of thoroughly skilled arquebuse-men embodied in the old French bands in Picardy and Piedmont secured advantages to the Catholic armies.  In the opposite party, a young general who was destined to become a great king, endowed with that creative instinct, that genius which is as readily applicable to the science of government as to that of war, and which, when tempered with good sense, may bestow glory and happiness upon whole nations, Henry IV., had taken particular pains to increase the number and the efficiency of his arquebuse-men, and frequently managed to employ them in ways as novel as they were successful.  At the Battle of Coutras, he distributed them in groups of twenty-five, in the midst of his squadrons of cavalry, so that, when the royal gendarmerie advanced to charge the latter, they were suddenly received with murderous volleys by these arquebuse-men of the spur, as they were called, owing to their combination with the cavalry, and the shock they thus encountered gave victory to the Protestants.  Henry IV. went even too far with his passion for fire-arms.  He increased their number and their use among cavalry so extravagantly, that the latter arm was perverted from its proper object.  The cavalry, for a long time, forgot that their strength lay in the points of their sabres, in the dash of the men, and the speed of their horses.