Roman Arrowhead Penetration - A truly objective testINTRODUCTION
Reconstruction archaeology at its best should try and give objective data, but little attempt has been made to quantify the effectiveness of ancient to medieval weapon systems. Much that there is can be traced back to W.T. Thomson “An Approximate Theory of Armour Penetration” 1955. However the conclusions reached are at best highly questionable. P.H. Blyth attempted the task for the Greek Persian wars. Using a “ballistic pendulum”and taking into account a certain amount of give in the target he produced more plausible estimates.
While some weapons may seem more impressive than others, a whole host of variables must be taken into account. Weapons with a narrow cross section designed to penetrate will be more efficient than others with broad cutting heads. So for example, amour piercing bodkin arrowheads penetrate deeper than those with broad hunting heads designed to cut muscle and blood vessel. The performance of arrows is further complicated by their weight, size and drag through the air. Heavier arrows with large heads produce high drag, and are therefore better used at close range. The performance of armour is equally difficult to quantify. The quality of metal armour varies, while the effect of soft or low-density material often worn under metal armour will rob the weapon of its momentum, reducing its impact. And as Vegetius realised, weapons have greater effect when aimed from a height.
Rather than welcoming such efforts at objectivity, experience makes me sceptical. Modern reconstructions of weapons and armour are very rarely made using the same techniques and materials as originals. They differ in hardness and sharpness. The same blade can be used by two individuals with greatly differing results, depending on their strength, the angle of cut, and the response of the target. Rather than just hitting the target with the blade, which often causes it to bounce off, the sword edge needs to be drawn deeper into the wound with a deliberate cutting motion. Generally targets will back away at the moment of impact, reducing the momentum of the weapon. Armour that may adequately protect the body, will not cover target areas such as the eye sockets, or the veins and arteries in the neck. It is safe to assert that missile weapons have greatest momentum at close range, for example 50m and under for arrows. It is possible to use the cliché that, as in all periods, there was a race between weapons and armour protection.
The reconstruction of Roman bows cannot be an exact science. Little is known about the actual style of construction used for 4th century Roman recurved bows. The length of some of the bone and antler ear laths suggests the bows were not as heavily recurved as later Mongol examples, and that they were asymmetrical, with the upper limb taller than the lower. This is useful when riding. A partially surviving Parthian weapon from Baghouz has been reconstructed. Known as the Yrzi bow after the area of the cemetery where it was found, the reconstruction had a draw weight of approximately 60-80lb. But the Middle-Eastern tradition of bow making would differ from that of the Huns of Central Asia, and possibly from whatever methods were used in the state fabricae. The Central Asian influence can be seen in the “Qum-Darya Bow”, found in a mass grave associated with a Chinese frontier post. Dated from the 1st century B.C. to the 3rd century A.D. similar ear and grip laths spread west with Hunnic influence. They are found in western Europe on such sites as Blucina and Wien-Simmering. Such bows used up to seven ear and grip laths, compared to four on the Yrzi bow.
Modern recurve bows cannot truly mirror those of the past. In the same way modern powerful yew self-bows do not exactly correlate to archaeological finds. The author’s best 80lb bow is made from slow-grown North American yew, Taxus brevifolia. Grown in Oregon, it has a close grain without knots, and is an approximation of a Roman self-bow. European yew, Taxus baccata, would give a better cast and be more efficient but is rarely available today for making high poundage bows.
Arrows were either broad heads or trilobate designs to cut as much muscle and blood vessel as possible, or narrow bodkins designed to penetrate shields and armour. Arrowheads can be socketed or tanged. A shaft with a tanged head will be susceptible to breakage in some conditions. The weight of head will effect the distance the arrow can be shot. Light 40g flight arrows can travel over 200m from my 80lb bow. Indeed Vegetius states targets should be set up at 600 Roman feet (177m). However it is probable that a selection of light, medium and heavy arrows would be carried to allow the archer to respond to a variety of threats.
Heavy 70g arrows will have their greatest velocity during the first 50m of flight, and be used at relatively close ranges. Light arrows would allow a target to be peppered at 200m. The arrows from Dura and Micia in Roman Dacia were made of reed with wooden foreshafts to take the arrowhead. But arrows from bog burials give us versions of western-style arrow construction from solid pine or ash. Shafts had parallel sides, but were tapered slightly at the fletchings widening again at the knock to prevent breakage. This shape of shaft would also mean the arrows would leave the shaft cleanly. James suggested that the nature of the wooden foreshafts at Dura were not designed for holding a metal head, and the reed arrows were primarily for hunting or for target shooting.
I have experimented with reed arrows and found them too weak to be shot from high poundage bows. They do seem better suited to weaker hunting bows. Fletchings were not “corkscrewed” about the shaft to impart a spin. Such a system would only increase drag. The natural curvature and twist of the feather will impart a spin giving increased accuracy. Surviving fletchings from Dura show that western and eastern styles were used in the east. In the west a recognisable cock-feather lies at ninety degrees to the knock, in the east one of the three feathers is on the axis of the knock. Western style fletchings would also stop around 25mm from the knock to allow the fingers to grip the arrow. Eastern style fletchings can be taken to the end of the knock.
There have been many tests of bows and arrowheads. But to be successful as many variables as possible need to be constant.
If using a bow the same bow needs to be used for each shot, pulled to a constant draw length, with a constant clean release. It would of course be easier and more object to use a machine to shot the arrow with a consistent velocity time and time again.
The weather conditions need to be considered. Wind direction, air pressure and humidity all need to be taken into account. They effect not just the bow and the bowstring, but the arrow as well. For example moisture on the flights increase drag and weight.
The target needs to be uniform and consistent. Some people get upset about the use of meat, which can be impressive, but is seldom consistent. Pigskin is 3 times as thick as human skin, so needs to be skinned if it is to represent human flesh. In reality the thickness of human skin varies, and the thickness of the skull and its round shape makes it a tough target. A target that is set at 30 degrees will deflect the arrow; effectively doubling it’s own thickness. Ballistic gel is a constant density, but lacks bone and blood vessels.
The arrow shafts also have to be consistently the size, weight and profile, which is hard to achieve using period materials. War arrows in the medieval period had longer flights and the shafts often widened towards the point. Hunting arrows would have a different profile.
Such variables, coupled to the use of modern materials makes objective testing impossible. Or does it?
A TRULY OBJECTIVE TEST
There now will follow a description of the most objective test of arrowhead penetration I am aware of. It is in many ways perfect. The weather conditions were constant, the arrows all had the same kinetic energy, were used at the same moment and at the same target, myself.
Each autumn my gear is methodically cleaned, sharpened and stored in my equipment room. It is a therapeutic way of “pulling the curtain down” on a summer of high adventures and enjoyment. The room holds more helmets, armour, swords, shields, clothing, and footwear than I care to think about. Arrows are carefully repaired, cleaned, sharpened and oiled. Then they are stored in a 15th century style arrow basket with a typical bell-like shape. The heads of the arrows are held tightly protruding from the top of the basket, while the wide bell end of the wicker construction protects the flights. The arrows have shafts of a constant length, and are held tightly within the basket.
One autumn I was precariously balanced on a dining chair happily hammering another nail into the wall to hold yet another bit of equipment. Finishing my work I faced away from the wall and raising my arms up above my head, jumped down from the chair. As I brought my arms sharply downwards, the underside of my right forearm impaled itself on the arrowheads held upright in the arrow basket.
The arrows were propelled with constant force into one specific area of human flesh, the thickness of the skin been constant. In fact every variable was constant, except for the shape of the arrowheads involved. It was the perfect objective test.
The only factor that reduced the validity of the test was the fact that the tester went into shock. I was in no fit state to start gathering data, or even to take photos. Instead I felt dizzy, sick and weak at the knees. I sat on my bottom stair and vomited into a bucket, which is I suppose a result of sorts. I have never read a report where the ballistic gel or the dead pig goes into shock, so perhaps this is an important bit of data. If you get an arrow stuck in you, even one causing only superficial damage, you will probably go in to shock. However I am proud to report that after a short time, self-interest and my spirit of archaeological reconstruction came together and I started examining the wounds.
After wiping away the blood I could count 16 puncher wounds, the majority from narrow bodkin warheads. The short bodkins had barely penetrated the skin, but they had dissipated the force of the impact. The long narrow bodkins, typical of the German limes, had left a series of square shaped holes. These were not bleeding greatly but were painful. The heads are designed to penetrate rather than cut, and I suspect they are better at penetrating a layer of armour. The heads have a good ballistic shape through air, but the gradual resistance of flesh seemed to defeat the design. The thinnest bodkin head had actually been bent under the impact of my forearm, and this seemed to be a case of a bodkin made of iron meeting a cavalryman made of steel.
The trilobate heads left easily recognisable wounds. But once again penetration was not impressive, except for a relatively long narrow example which did cause a lot of bleeding. This particular design seemed to offer the benefits of penetration coupled with cutting edges. Once again these heads produced relatively a lot of pain. I suspect these heads were causing bruising on top of their cutting action. Each head left three small cuts in my arm radiating from a central point. In reality if one of these cuts had been closed by stitching, the other two cuts would have been pulled open. These arrows make a wound that cannot be closed. If they do not kill you immediately, in five days time you could be dead from infection.
But hunting broad heads caused all the impressive wounds. These arrowheads are designed to cut flesh, muscle and blood vessels and they did a fine job. Particularly impressive was a broad head with a very narrow blade-like cross section. It had slipped in deeply, cutting a broad path into my forearm. It bled more than all the other wounds put together. The more I examined this wound the less impressed I became as I tried to stop the bleeding.
My wife allowed me to wash the wounds in honey, but drew the line at using sphagnum moss to soak up the blood. Wound clamps were not applied, and I have two scars to this day.
So when I read another report on the relative penetration of arrowheads I do so with a tolerant expression of one whom knows more than the testers can guess. But I also get a slightly sick feeling in the pit of stomach and I appreciate the joys of armour even more.