Dictionairy of Siege Engines

A

Antibasis: Short part of the base of a Ballista, standing on the ground to prevent it from falling over to the front. Together with the basis it forms the eschara (the base).

B

Ballista: See the Ballista page.

Basis: Long part of the base of the Ballista, standing on the ground to prevent it from falling sideways. Together with the antibasis it forms the eschara (the base).

Bracchium: Throwing arm, generally made out of ash. An Onager has one, a Ballista has two.

C

Carchesium: Winch drum. You put the winch lever in one of the holes in the drum to winch down the throwing arm.

Cheiroballista: See the Cheiroballista page.

Chelonium: Slider, the part of a Ballista that slides backswards and draws the arms.

Columnae: Vertical piece of the base of a Ballista. The basis and antibasis are fixed to this.

E

Epizygis: Piece of steel where the cord bundle is wrapped around. You use a long steel lever made in such a way that you can put it around the epizygis to tighten it up.

Eschara: Base of a Ballista. It consists of the columnae, basis and the antibasis and can be taken apart for easier tranportation. Picture

F

F.A.T.: A Floating Arm Trebuchet isn't an ancient siege engine, but a machine developed by mathematicians to further improve the efficiency of the trebuchet. In my knowledge it is the most efficient siege engine ever invented. Picture

Gastrophetes: See the Gastrophetes page.

Greek Catapulta: See the Greek Catapulta page.

M

Modiolus: An important piece in all torsion-powered siege engines. It is made out of five parts, a plate with one big hole and several little holes around it fixed to the frame, a piece of tube (this is the actual modiolus) which fits into the big hole of the plate, a round plate fitted with holes and welded to the big tube, a smaller piece of tube (this is the epizygis) fitted at a right degree angle to the modiolus and finally a pair of small pins to hold the round plate into the correct position. All the parts are made out of steel, but the Romans only used cast bronze. If you want more torsion (more range) to throw the projectile further, you take out the pins, tighten up the cord bundle and put the pins back in place. The pins prevent the round plate from slipping back and releasing the torsion. An Onager has two of these, and a Ballista has four. Picture

O

Onager: See the Onager page.

Oxybeles: See the Oxybeles page.

R

Regulae: Short frame beam. An Onager has four of these.

Regula Exterior: Outer frame beam. An Onager has two of these, which are fitted to the regulae. Roughly in the center is the hole for the cord bundle.

S

Scorpio: See the Scorpio page.

Scutula: Winch lever. You insert this into the winch drum to lower the throwing arm.

T

Trebuchet: A medieval siege engine relying on a counterweight to launch stones to a target. It was invented during the Midlle Ages and is the biggest siege engine. Picture

Traction Trebuchet: The same machine, only the counterweight consists of people instead of rocks or lead. Picture