First off, let me apologize for the yuk factor in this posting.  I wouldn’t include all the graphic detail if it weren’t necessary to flesh out the argument   …….  so to speak.

To start off, here again is the Maiden Castle skull from 43 BC.  We are attempting to see if the square hole in the artifact could have been caused by one of Vespasian’s ballistas.

I finally got around to measuring the velocity of the shot that produced a square hole in the frontal bone of our pig’s head.  The 6500 grain bolt was only traveling at 105 fps,  a fairly remarkable speed given the short 13″ draw length that was used. The bone that it penetrated was almost 7/8″ thick, with a honeycombed appearance on the inner side, and unlike the dried out sheep skulls used by Mr. Wilkins in a similar experiment, ours were still nice and juicy.   Here is that photo of the wound created by a ballista bolt going a very  slow 105 feet per second.

While this shot demonstrates that a square-headed ballista bolt can indeed create a square shaped hole as seen in the Maiden Castle skull, it also provides some indication of how difficult it is to do with a moving projectile.  If the velocity of the bolt had been any greater, it would have resulted in a depth of penetration that took the bolt head beyond the  square cross section and into the increasingly round portion that matches the shaft diameter.  The tip that we were using was a functional duplicate of this very popular original:

And so, to restate:   Our tests indicate that any over-penetration beyond the square, quadrobate section of the head simply smahes out any clean cut square hole, turning it into a more jagged shape that can accommodate the larger diameter round section.   A pretty obvious state of affairs that backs up Mr. Wilkins conclusions on the matter.

Given that the temporal bone on the Human artifact is probably only 3/16″ or so thick compared to the 7/8″ thick frontal  bone of our test subject,  the velocity of any bolt would need to be many times slower than the 105 fps used in our tests if it were going to make a clean square sided hole in a relatively frail human skull.  In fact, shots taken into the thinner,  5/16″ temporal bones of our pig’s head proved difficult to control down to a level that only the quadrobate section of the tip made entry.

When a pilum was used to pierce the pig’s skull,  instances of over-penetration only resulted in a nice clean cut square hole.  Again, a very obvious outcome given that with the shank of a pilum,  the largest cross section that moves through the bone is never any greater than the square sided tip.   The size difference between our test subject and a plastic model of a human skull, can be seen below.

In conclusion, while it is possible for a ballista bolt to make a square shaped hole in a skull, it is highly unlikely.   On the other hand, just as the Wilkins team discovered,  a typical pilum will nearly always leave a square sided wound when thrust into cranial bone.


Denouement:      The Rebecca has a  comment on all this Maiden Castle, bolt-in-the-skull silliness.  Her exact technical appraisal is,    “Eeeeew!”.

Can’t say I disagree with that.

One final creepy thought —- there is no doubt that Vespasian’s,  Second Augusta Legion used ballistas on the defenders of Maiden Castle.

These famous artifacts displayed in the Dorchester museum, show that the broad shouldered fellow on the left stopped a ballista bolt with his spine.   Standing up to Roman imperial ambitions was clearly a risky business.

2 Responses to “Wrapping the Maiden.”

  1. Michiel says:

    Do you think the skull of the photo on below website could have been inflicted by a Roman ballista bolt:

    It has been found where archeologists now believe to have located a battle between Caesar and 2 Germanic tribes.

    The hole in the skull was commented upon as inflicted by a Roman weapon. To me – a layman – it looks like the neat edges on side of the hole betray a square diameter projectile head. Whereas the damage to the other side of the hole may well have been caused by the following shaft.

  2. nick says:

    Dear Michiel, my apologies for not getting back to you sooner. Your question got lost in my interminable spam file. As to whether or not that obviously mortal injury was inflicted by a projectile or not, there are really too many imponderables to know with any certainty. If it were not a through and through, (that is the projectile going all the way through, out the other side and clattering on the ground) then a square sided exit wound caused by a square sided projectile head just protruding from the skull, followed by a round entrance wound caused by the damage from a round shaft following along, makes perfect sense. Such an injury could be consistent with either an arrow, or ballista bolt if the latter were fired from some great distance. At closer ranges, 100 yards an less, I suspect that even a moderately powered ballista like a skorpion would have had it’s bolt slip right on through without undue resistance. But again, it is very hard to know with any certainty. Battlefield execution, or combat involving a pilum, is probably more likely. Beyond conjecture, I fear there is little else to say.

    Thank you for the question though. I forget sometimes that someone may actually be reading my blog. It was good to hear from you. Nick.

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