The Europeans’ main weapon against the invaders were horse-solders or cavalry. The idea of cavalry was not a new one. The Ancient Greeks and Romans had used horse-soldiers but they had never taken the place of their heavily armed foot-soldiers, or infantry, because they could not charge the packed ranks of the enemy’s foot-soldiers effectively.
Before the invention of stirrups, cavalrymen had the greatest difficulty fighting on horseback. If they wore heavy armour, they were likely to lose their balance. If they charged their enemies with their spears extended in fron of them, they were likely to be swept from the saddle by the impact. But with stirrups, the medieval knights were able to do combat sitting firmly in their saddles.
Historians think that stirrups were invented in China at the end of the fifth century AD, but it took a long time for news of their use to reach the west. However, once the Europeans started using stirrups, other developments followed rapidly. Long pointed shields were designed to cover the whole of the body and cavalrymen learnt to gallop at top speed into their enemies and stab them with their spears instead of throwing them. Their horses were shod with metal shoes so that they could travel over the roughest ground without splitting their hooves. It was possible for a rider to wear heavy armour without losing his balance when leaning forward or backwards.
The day of the infantryman was over, and the day of the cavalryman or knight had come.
As a knight’s armour and war-horse were so expensive some means of paying for them had to be worked out. Instead of hiring and equipping ordinary soldiers, the medieval kings preferred to give away part of their lands to their followers. They governed the estates for their king and supplied him with soldiers whenever he needed them. This brought into being a new system of landholding. It was called the feudal system and it produced a new kind of soldier, the knight.