You may have thought that castles had huge garrisons. But in fact, their numbers were small, for these professional soldiers had to be paid during times of war and times of peace. When attack came they relied on the help of people who normally did working jobs.
Because they did not have huge defending forces, castles relied on being strong enough to stand up to attack and give the defenders the best possible defence. Because of this, very few castles were taken by force. Most were put under siege and starved out.
