design. However, the matchlock design was superseded in the 1690s by the flintlock musket, which was less prone to misfires and had a faster reloading rate. By this time, only light-cavalry scouting units, "the eyes of the army", continued to wear front and back armour plates to protect themselves from distant or undisciplined musket-equipped troops. While soldiers armed with firearms could inflict great damage on cavalry at a moderate distance, at close quarters the cavalry could slaughter the musket-armed infantry if they could break their formation and close to engage in melee combat. For many years infantry formations included a mix of troops armed with both firearms to provide striking power and pikes to allow for the defence of the arquebusiers or musketeers from a cavalry charge. The invention of the bayonet allowed the combining of these two weapons into one in the 1690s, which transformed the infantry into the most important branch of the early modern military—one that uniformly used flintlock muskets tipped with bayonets. Nature of war This period saw the size and scale of warfare greatly increase. The number of combatants involved escalated steadily from the mid 16th century and dramatically expanded after the 1660s. For example, the King of France could field around 20,000 men in total for his wars against Spain in the 1550s, but could mobilize up to 500,000 men into the field by 1700 in the War of the Spanish Succession. Moreover, wars became increasingly deadly in this period. This may in part be attributed to improvements in weapons technology and in the techniques of using it (for example infantry volley fire). However, the main reason was that armies were now much bigger, but logistical support for them was inadequate. This meant that armies tended to devastate civilian areas in an effort to feed themselves, causing famines and population displacement. This was exacerbated by the increasing length of conflicts, such as the Thirty Years' War and Eighty Years' War, which fought over areas subjected to repeated devastation. For this reason, the wars of this era were among the most lethal before the modern period. For example, the Thirty Years' War and the contemporary Wars of the Three Kingdoms, were the bloodiest conflicts in the history of Germany and Britain respectively before World War I. Another factor adding to bloodshed in war was the lack of a clear set of rules concerning the treatment