Effectiveness
As a low-velocity firearm, the arquebus was used against enemies who were often partially or fully protected by steel-plate armour. Plate armour worn upon the torso was standard in European combat from about 1400 until the middle of the 17th century. Good suits of plate would usually stop an arquebus ball at long range. It was a common practice to "proof" (test) armour by firing a pistol or arquebus at a new breastplate. The small dent would be circled by engraving to call attention to it. However, at close range, it was possible to pierce even heavy cavalry armour, heavily dependent on the power of the arquebus and the quality of the armour. This led to changes in armour usage, such as the three-quarter plate, and finally the retirement of plate armour from most types of infantry.
While the power of the arquebus was of great advantage to modern militaries, they were not practical in Europe until the Dutch, or in Asia the Japanese, developed the concept referred to now as volley fire. Volley fire allowed armies to turn their usual formation into a rotating firing squad with each row of soldiers firing a shot then marching to the back of the formation to reload, a technique first proposed by Aelian. Willem Lodewijk describes drilling soldiers in a similar manner to how Aelian "countermarched" his troops; 'I have discovered ex evolutionibus a method of getting the musketeers and soldiers armed with harquebuses not only to keep firing very well but to do it effectively in battle order (that is to say, they do not skirmish or use the cover of hedges ) in the following manner: as soon as the first rank has fired together, then by the drill they will march to the back. The second rank, either marching forward or standing still, fire together then march to the back. After that, the third and following ranks will do the same. Thus before the last ranks have fired, the first will have reloaded, as the following diagram shows: these little dots : : show the route of the ranks as they leave after firing.' Once volley firing had been developed, rate of fire and efficiency had increased and the arquebus became the most effective tool available to the late 16th century armies that carried them. Once volley fire was established, the arquebus went from being a support weapon to the primary focus of early modern armies.
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