The Trebuchet was a masterpiece of engineering. It was the mightiest military tool for over 300 years until the advent of cannon. First used in the early 11th century this engineering marvel was perfected no later than 1150. The design, development, deployment and usage of such a towering machine clearly indicates that Medieval society was advance, wealthy, scientific and comprised of master timbermen, craftsmen, military engineers, and designers who knew science and math. No other society in the world could have developed anything comparable. Nor did they.
Trebuchet's were enormous usually 5 or 6 stories [60 feet] in height. The weapon was basically a large swinging see-saw, with a thick weighted end or ballast, swinging a slimmer lighter end furnished with a 200-300 lb rounded stone contained in an open sling. Tension, gravity, and force propels the arm and its stone against a stopper which sends the projectile hundreds of feet.
It would take at least 40 men to build this structure and then operate it. It was extraordinarily costly. Melted down iron, or 4 tonnes or more of dirt and gravel were used as counter-weights, only adding to the cost of the weapon. It also had to be built near to the siege which added a considerable amount of complexity to sourcing supplies for the structure, and then assembling the unit in time for battle.
The Trebuchet is the manifestation of a complex society profoundly impressed by and pursuing, higher science and math. Such a machine can only work if you understand, leverage, weights, counter-weights, tension, velocity, gravity and object-acceleration. This means that gravity for instance, was not only understood, but being used in practical affairs some 500 years before Newton. The same is true of velocity and speeds of weights fired over distances. The Merton 'calculators' of Oxford, prevalent and influential by 1250, had developed the supportive math for gravity, velocity and mean speeds of objects 400 years before Galileo took credit for inventions he never created.
Trebuchet's were magnificently effective. If a castle was besieged by a Trebuchet, it was only a matter of days before part of the castle wall would be annihilated and caved in. Edward I's campaign against Stirling castle and his use of a massive swinging Trebuchet some 300 feet in length and perhaps 100 feet high, named the WarWolf devastated the stronghold in a matter of days. This gave Edward I [1239-1307] the nickname Malleus Scotorum or 'The Hammer of the Scots'. No kidding.
A 'dark age' could not build a Trebuchet. Period.