Siege Weapons - Perrier

In November 2003, the perrier below was filmed by Online Productions "Bloody Britain" series hosted by Rory McGrath. This allowed us the opportunity to throw some reasonably authentic fire-pots (clay pots filled with burning pitch - don't try this at home!) at a wooden "bridge" target. Filming took place at Regia Anglorum's Wytchwood site near to Canterbury. Rory had a go as one of the perrier crew, and we didn't singe a single hair on his head!

Spring 2005 - the perrier is now being revamped to increase height and provide more substantial bracing for the base.
Typical Trebuchet

A perrier is one of the family of weapons based on the counterpoise principle - a heavy weight at one end of a beam is used to throw a much smaller projectile (e.g. rock!) at the other end of the beam - imagine an unbalanced see-saw. A sling was normally used to increase range - as the long end of the beam rises the sling whips over, releases itself and hurls the projectile - hopefully toward the enemy, but sometimes not!

A counter-weight trebuchet (left) used the force of gravity as the the power to move the beam, the design included a large weight (such as a large wooden box full of stones, or of lead from a handy church roof) attached to it. These could be up to 10m high, with a counterweight of several tons (or tonnes).

With a traction trebuchet or perrier ("rock thrower" - petraria in latin, petrobolos in Greek), the power was provided by human muscle. A team of people would haul down on ropes hanging from the short end of the beam. The perrier on the right is from the siege of Carcassonne in 1209.

 Larger perrier, Carcassonne Cathedral, 1209

Parts of a Perrier

hauling ropes haulers upright support spreader pivot archers for protection throwing arm (beam) sling hook sling sling operator

This image, from the Chronicle of Petrus de Eboli (around 1180, though some attributions state later), clearly shows the key elements of a small perrier. Move your mouse over the following list to identify the various features:
General view of our Perrier, in its latest incarnation

The Albini Perrier

This is the smallest form of pole-framed perrier found in period manuscripts (e.g. Chronciles of Petrus D'Eboli or Skylitzes Chronicle, early 13th century). There are records of this type of perrier being used by Normans in Italy and Byzantium from the early 12th Century.It is primarily an anti-personnel weapon for use from fortifications rather than in the open field, designed to keep heads down.

The Greeks had specific terms, lithobolos ("stone thrower") or alakation, for a smaller (probably pole-frame) perrier such as this, while a pole framed "hand trebuchet" designed to be operated by a single man was termed a chieromangana. For more information, a translation of Anna Comnena's (daughter of the Byzantine Emperor Alexius I) "Alexiade" is recommended.

The main dimensions are:

  • Height (to pivot) - 2.5 m (now being increased to 3+ m)
  • Diameter of Upright - 46 mm (roughly octagonal)
  • Diameter of Beam (arm) - 35mm (roughly octagonal)
  • Hauling arm length - 0.8m
  • Throwing arm length - 2.3 m
  • Sling lengths - 0.85m and 1.0m

Ash is used throughtout, except for the pivot which is currently made of a 3 inch diameter section of garden fence post (exact type of wood is indeterminate). It is intended to replace this with a piece of ash of suitable section, though it has lasted to date. For maximum strength no holes are cut into the beam (apart from one for a small peg to hold the hauling ropes in place), or into the upright post.

There is no spreader on this perrier - the hauling ropes being attached directly to the end of the beam. This effectively limits the hauling crew to two or maybe four people - any more would get in each other's (or the beam's) way.

The pivot head is assembled with wedged tenon joins, which are both authentic to period and allow it to be dismantled into a "flat pack" for travelling. Ropes are either jute or manilla, the latter due for replacement when some suitable hemp rope can be obtained.

For ease of assembly, the upright is located into a rather inauthentic piece of pipe (scaffolding pole) driven into the ground. This was subsequently augmented by tripod bracing that is lashed to the main upright, and pinned to the ground with large stakes.

The hook is 8mm diameter iron rod forced into a hole in the end of the beam. The hook angle was initially about 40 degrees, subsequently reduced to around 20 degrees with improved range. A length of rivetted iron strip forms a reinforcing collar around the hook end of the beam.

The beam passes through a hole cut in the pivot, and is tied with rope locating in some shallow grooves cut into either side of the beam. Following initial tests, this was augmented by a small ash pin inserted through the pivot to just penetrate the beam - this solves any tendancy for the beam to slip in the pivot.

 Close up of the pivot head (Goodrich castle in the background)
Preparing to fire, the beam is starting to bend

In Use

One unusual feature of this light form of perrier is that the throwing arm can be tensioned and bend just before loosing the missile, adding additional impetus. This takes coordination between the haulers and the sling operator - tension is pre-applied to the ropes before the sling and missile are released. Murdi al-Tarsusi's "Instructions of the masters on the means of deliverancce in wars from disasters..." from 1187 (Bodleian Libary, MS Hunt 264) contains instructions on how best to operate a perrier such as this.

Missiles used to date have been onions (for initial test firings - just to be safe), raw eggs (they bounce, even after a 50 yard flight), and (where safe) rocks.

With the current 20 degree hook angle, the 0.85m sling gives a reasonable trajectory, with a range of 100+ yards, and a maximum height of about 50 feet. Correct selection of missiles is required to optimise range - a mass of 1-2 lbs (0.5 - 1.0 Kg) appearing to optimise energy transfer - smaller missiles generally result in decreased range.

The longer sling (1.0m) gives a flatter trajectory - more like a cricket bowler, with a range of 30-50 yards.

A third, shorter (about 60cm), sling will be made for the perrier's next outing - this should (in theory) give a very high lob.

Just after firing, the sling has wrapped itself around the beam, the upright has tilted forward in the soft ground View down range - 1/2 kg rocks were hitting the tree covered side of the moat visible in the background (Goodrich Castle, May 2002)

Bibliography:

Nicolle, D; Arms and Armour of the Crusading Era 1050-1350, Greenhill Books,1999