Warfare techniques in medieval times were brutal and drawn out compared to the quick strike attacks used in today's modern battlefield. Mostly, the equipment used by medieval soldiers dictated the type of tactics they could employ. Technology was often the deciding factor in a battle during the Middle Ages, which lasted from about the fifth century to the 15th century.
Siege engines were used to attack any fortified building such as a keep, fort or castle during medieval times. Stronger siege engines were constantly being developed to reduce the protection afforded by sturdy, stone walls. A trebuchet, for instance, could hurl rocks weighing 90.7 Kilogram at the walls of a castle. Castles were also attacked from underneath. The attacking army would attempt to dig under the foundation of the wall and then set fires in an attempt to weaken the fortifications.
In a land battle where two armies faced off across a given space, conflict was often short, bloody and over in a remarkably short period of time. Tactics that were effective mostly revolved around using the most advanced technology available at the time. The invention of the stirrup and better armour gave way to the mounted knight. A charge of knights proved devastating even to the highly trained Roman armies. However, the development of the English longbow and trained bowmen quickly reduced the knight's usefulness. An army would launch flight after flight of arrows at the charging knights and reduce the force greatly before the soldiers could even reach the opponents.
The primary method of defence in the Middle Ages was carried out far before a battle began. The design and building of fortified enclosures was the best defence in those ages. Those who built the most impenetrable castles pulled back behind the walls and chipped away at enemy forces from a position of power. Wall design, moats, a portcullis and methods of attacking the opposition forces from atop the walls provided many defensive opportunities. Defenders would pour down things like fire or hot oil onto attackers to dissuade them from attacking. The elevated position also provided a good vantage point for archers.
Patience was one of the greatest defences for a besieged army. Due to harsh camp conditions, disease was a large threat to an army executing a sustained siege. An army attacking a castle sometimes offered to enter peaceful negotiations. Also, if a castle could hold out long enough, word of the conflict would often reach allies who could send supporting forces. As a result the attacking army could be caught between the castle and the relieving army, a very unenviable position.