Medieval warfare tactics often revolved as much around defeating the other army in battle as they did infecting enemy soldiers with some disgusting disease or humiliating them into surrendering. For these reasons, the life of a medieval soldier tended to be short and miserable.
While engaged in a protracted medieval castle siege, soldiers on both sides searched for all sorts of awful things to throw or shoot at each other besides your average arrow. What they put in catapults varied from massive rocks to truly terrifying ammunition like beehives or even barrels of poop.
In many ways, siege warfare was nothing like the heroic battles depicted in films. The most important skill for a soldier was strong improvisational techniques. Sometimes that meant standing their ground and fighting off attackers in close quarters hand-to-hand combat, but other times it just meant several hundred men chucking poop at each other and calling it a day.
As attackers approached the walls of a castle or town, it became increasingly important to slow them down. Defenders needed to rally against the strongest points of the enemy’s attack. One effective method of slowing an assault was to throw massive amounts of live beehives along the attacker’s approach.
As soldiers pressed their attack, they’d inevitably stomp on the beehives, unleashing swarms of furious insects looking for somebody to sting. It often became so painful soldiers could hardly use their hands.
The only alternative was walking on eggshells to avoid upsetting angry bees, but that’s not the quickest or most effective way to assault a defended fortification.
Over the centuries, castle design improved. Because they were always in danger of a possible siege, castle designers needed new ways to thwart enemy attacks. Moats and strong walls did some of the work, but they needed a way to defend the large door everybody came in and out of.
To that end, latter castles were designed with “murder holes” that allowed defenders to drop all sorts of things directly on an attacker’s head. They were almost impossible to shoot up through from the ground, but defenders could easily plop a few rocks or burning liquid through the hole.
Greek Fire was originally invented and used by the Byzantines in the Middle East. Though the exact formula has been lost, Byzantines somehow found a way to shoot fire through a hose like a medieval flamethrower.
At first Greek Fire was limited to naval engagements, but many scholars believe it was eventually used in some land-based conflicts and sieges. Richard I is believed to have gotten his hands on the Greek Fire formula after the Third Crusade and used it in his own land battles for at least a few years.
When conducting battles in Europe during the age of chivalry, everybody not involved in combat was usually allowed to flee the scene unscathed. In the Middle East, Europeans decided those old rules didn’t apply, and anybody could become a target.
If a castle or city decided to wait out a siege and not immediately surrender, they’d often send messengers just to let the attackers know it was going to be awhile. If the attacking force was particularly angry, they’d cut off the messengers' heads and fling them over the wall via catapult.
Sometimes they’d just throw over the entire body.