A large number of the nobility in England joined the king's army. At that time, upper-class men were trained at a young age to ride horses. This meant that Charles had the advantage of having a very good cavalry. Parliament's soldiers gave them the nickname Cavaliers (Spanish horseman called cavalieros had been responsible for killing Protestants in Europe).

The king's nephew, Prince Rupert, was put in charge of the cavalry. Although Rupert was only twenty-three he already had a lot of experience fighting in the Dutch army. Prince Rupert introduced a new cavalry tactic that he had learnt fighting in Sweden. This involved charging full speed at the enemy. The horses were kept close together and just before impact the men fired their pistols.