Siege weaponry was to the Medieval people what Big Bertha was to the allies; a machine that fucked your shit up.
Siege Weaponry, as the name implies, was weponry designed to siege the enemy's fortress and bring the walls crumbling down. While many different types exist, the Roman designes and models seem to be the most popular and enduring.
The Onager, more commanly called the Catapult, is probably the best known of all the siege weapons; by using an arm racheted back with rope or sinew on a wood frame, the siegers could launch rocks, balls of burning tar, or ceramic shrapnal balls over a hundred yards with force enough to shatter walls (and bones). Weather or not it was tested with actual cats is disputed.
As well knows if not as well pronouced, the trebuchet was similar to the catapuls, but it couls only fire ceramic and stone projectiles due to its fireing mechanism; a huge net that fucking slung them at the enemies walls. When the arm was pulled back, it would pull up a giant weight on the other end, and when released, the weight would swing down, causing the arm to swing forward and release like Roy Halliday, if Roy Halliday was interested in tearing down a giant, reinforced city wall.
Plural 'Ballistae', these where giant fucking crossbow that fired bolts rangeing from the size of a broadsword to a goddamn horse. Using arms held by twisted sinew or rope, the men arming the Ballista (no less than two, no more than ten) would wind the arms back with a racheting crank and load the bolt on, relasing it to fly over 400 feet, either demolishing the person it hit or peirceing the castle walls, so that siege ladders could be hauled up.
Exactly what it soulds like, the Tower was a mobile fortress with stairs and platforms inside, made to roll right up to the castle walls and open up over them, allowing entier troops into the cities defenses. This ment the invaders had to have good intel on the hight of the walls, or they'd really have egg on their face!
Or, you know, boiling tar and oil.
Testudo (literally 'Tortise')
Contrary to popular belief, 'Testudo' is not just an awsome name for a College Mascot. It actually is the Genus name for the Tortise, which is why the next weapon got its name. The Testudo was an wood frame covered with shields and could carry under it either a pendulum battering ram or armored soldiers. It was rolled right up to to the city gate and smashed through.
About as famous as the catapult, the battering ram was a large beam of wood baded with bronze, and later Iron, with some form of head on the bashing end, many times shaped like the animal it ot it's name from. The ram was used to bring down city gates and allow the invaders in to pillage to thier hearts content. It came in two formes, Pendulum, mounted under a Testudo, and hand-held.