you could use a battering ram to knock down the door. You could use a Siege tower to fire arrows or jump onto the castle , lastly you could dig underneath the castle and let the castle fall down.
because 1st of all there enamies and with no castles for the ruler there would be no way to rest and the other army would win because they were more awake than the other army
Treachery: someone inside who takes bribes to let you in or who tells you about the keeps weaknesses and strenghtsAssault : using battering rams and seige towers and ballistas also use a sappers tent...
Several ways. Attack directly, scale the walls, starve out the occupants with a siege, toss diseased animals and dead humans over the walls, dig under it and set a fire so the stones will start to...