The Comitatus Ballista
'Constantine'
	Back in early 2005 the committee suggested we should invest in Roman artillery. A very grown-up telephone poll showed the group massively backed the proposal. It was felt that artillery would add a new dimension to shows, and increase the public appetite for what we do. With no cities to besiege, or a lorry for transport, we didn’t need an onager. We would bend our efforts towards an iron framed ballista. And therein lies a universe of discussion, argument and counter argument. A Greek document “Heron’s Construction and Dimensions of the Cheiroballistra” describes eight mechanical parts, each described with a coloured diagram. Discovered in 1843, it was largely discredited until Dr. Eric Marsden identified it in 1971 as a description of a bolt shooting catapult, with metal frames and an arched strut, identical to those on Trajan’s column. The introduction of such machines can be dated to the end of the 1^st century AD, and they are recorded as being in use 1,000 years later. But there is more than one way of interpreting the document, and current reconstructions vary in size, design and capacity. Various other writers can be used to fill in some blanks, but there are issues around interpretation.
	Heron’s measurements produce a small hand portable machine. They are of relatively low poundage, but are viable weapons and could be the “hand shooters or scorpions” mentioned in Vegetius, with no stands or winches. However archaeological finds do suggest much larger measurements for some parts of the machine, Heron himself mentions winches in connection with torsion catapults, and the measurement given for the cross-section of the wooden case is 25% larger than for the old fashioned Vitruvian scorpio, suggesting the weapon is correspondingly more powerful. The new design allows the arms to move through a greater arc, by borrowing the palintone style frame used on stone throwing ballistae. But the spring frames are moved further apart giving greater power. Some have suggested the arms could swing inwards to increase the distance the arms travel and so generate more force. This is a 19^th century idea, and some archaeological finds seem to support the theory. However it is hard to believe that much of this greater swing would not be wasted until the bolt is actually propelled forward. However some testers claim that this is a more efficient system. The jury is still out.
	Many reconstructions use a simple winch system to pull back the trigger mechanism. The ratchet and pawl system used on our example is one possible interpretation of the illustration on the “Cupid Gem”, a seal stone showing the only side view of a Roman catapult. It is an authentic, and importantly, a safe system, despite the 700lb plus draw weight. In the future it would be interesting to field different interpretations of the iron framed design. However for our first machine we followed the work of Alan Wilkins, and our machine was constructed by Len Morgan, a well respected Roman artisan. He was a gentleman throughout and his knowledge and expertise is second to none. There are relatively few compromises in our design, and the performance is excellent. The machine is easily repaired in the field. New arms and whole spring assemblies could be easily fitted into a broken machine. The arched strut allows for accurate aiming, but the bolt cannot hit the frame in transit as with earlier designs.
	Modern nylon rigging rope is used in the springs. We explain that it has to be pre-stretched so when it is placed under tension no power is wasted. We haven't painted or dyed the rope black to look more authentic, we want the public to notice it. We need to explain how Romans used rope made from animal sinew, which would have had better performance than our modern substitute. But this is a working reconstruction of how things worked, we have had to compromise with the rope, and we should not hide the fact. After seventeen months the iron framed ballista arrived on a hot July day, just two days before the naming ceremony. The trials of pre-stretched rope, of exploding moulds, and messing around with the size of the wooden stand were left behind. After some quick tests on York racecourse, the proving ground for so much Comitatus equipment, the ballista was ready for the great naming ceremony.
	It was 25 July 2006, and 1,700th anniversary of Constantine the Great's proclamation as Emperor. It was a Thursday but we had still assembled a good size honour guard to escort the procession of religious leaders and leading bigwigs around York. The city's celebration of Constantine in dance, art and it's peoples hopes for the next 1,700 years sat uncomfortably with the reality of the actual event. It felt vaguely unsatisfying. However we played our part, tried to fill in any awkward gaps and generally made it up as we went along. After several hours out in the heat and sun we formed up and marched through the crowds to the Roman Baths public house, and downstairs to the Bath House Museum. Graham Harris had kindly lent us his museum for the naming ceremony, and the enclosed underground space made it feel very intimate and special.
	We had never done anything so formal before and it could have been a flop. But the whole thing was just for us, presented by us. It was great. I had a vague idea of what we should do, gave up trying to plan what we would do, and just did and said what seemed right. Steve intoned Latin prayers on one side, while Paul III and Jamie burnt incense on small portable altars. The ballista was christened with wine, oil, wheat, blood and a popular nut based snack. I don't know what I said, but it came from the heart. It was a very special occasion. The ballista was named Constantine, and I'm still getting used to that. The smell of incense, sweat, leather and iron gently made its way up the stairs and kept the public away. Then it was off to the pub!
	Constantine was a great hit at the Festival of History. We need to present it properly to the public, and it was parked out in it's own little area having pictures taken of it's most intimate workings. Its portability was tested as we carried it to and from the arena, and its range was tested as we shot dramatically across a lake. A few weeks later at Sewerby Hall Constantine was really tested each day. Dai took up the batten of ballistarius, and started destroying our targets. Currently Constantine is covered in three types of oil, sheepskins and plastic and is resting for the winter.
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