Brief Description:  A siege tower (or belfry) was a towering, mobile wooden fortress built to transport soldiers over defensive castle walls. Ranging from 30 to over 60 feet tall, these engines were constructed on-site from heavy timber, pushed by hundreds of men, and featured a drop-down drawbridge for deploying troops directly onto the battlements.

Key Features and Mechanics:

Structure: They were generally rectangular, multi-story frameworks designed to match or slightly exceed the height of the targeted castle walls.

Mobility: Mounted on four or more heavy wooden wheels, these towers were moved by oxen or pushed by infantry. Because of the weight, armies often built temporary flat wooden tracks over muddy terrain or filled-in moats to ensure the tower could roll smoothly.

Fireproofing: Because timber is highly flammable, siege towers were the primary target for defensive catapults, boiling oil, and incendiary weapons. To combat this, the exterior walls were entirely wrapped in non-flammable coverings, typically thick iron plating or fresh, wet animal skins.

Interior Layout: The interior was divided into several levels connected by ladders. The lower levels often housed a protected battering ram to smash through the wall or gate at the base. Upper levels carried pikemen and swordsmen awaiting the assault.

Combat Capabilities: The topmost platform was reserved for archers and crossbowmen to suppress the defenders on the wall as the tower approached. Once the tower was flushed against the stone fortifications, a heavy wooden drawbridge operated by a winch was lowered, allowing dozens of fresh troops to pour onto the ramparts.