A siege is when the enemy camp surrounds the castle until the people in the castle have no more food.The enemy would attack and try to conquer the kingdom and get their land. The reason they did a siege is so they can get more land ,workers and get power :)
A Catapult is a machine that was used for shooting enemies, castles and walls from the castles. They were used in ages A.D. 400-1500 to attack enemies and castles. Catapults can throw 450 to 500 m and its weight is 80 kg.