RomanArmyTalk

The problem of conveying specifications to Depeeka has led me to the question of whether the academic world has a methodology for measuring helmets other than using various semantic terminology. I remember from way back when I worked for the physical anthropology folks at the Smithsonian doing skull charts, which are exact side/top/front/back photos of the skull collection but reduced and measured precisely on several anatomical points of the skull (nasion-basion is the one I remember). If there isn't any discipline like this in the academic world, it seems like as good a time as any to propose it.
If accepted by the academic world, it would be a good gift from RAT, and something you Euros outthere could actually present at a conference.

But we do need to agree on a methodology, which points of the helmet to measure, what to name them, etc. I personally like the idea of ratios, since the Romans liked them so much, but exact measurements can be converted.

Considering the variation of helmets over the centuries, there are certain constants, like the length front back, the side to side, and the depth, but those exact points need to be agreed upon. Similarly to things like neckguard angle; measured from where? Some line drawings by Matt/Magnus show the distinct curve of the helmet from the side.

Thoughts?

Great idea Rich.

A set of specific points on each helmet sounds like it would work well.

That's a really good idea. Would this be a very vague start, or the kind of thing you're thinking of to add the terms to?

[url:3b0ek9tt]http://i75.photobucket.com/albums/i311/tarbicus/reference_points_01.jpg[/url]

I would also suggest, off the top of my head, that a common point of reference between all helmets would be where the front bowl cutout for the earguard meets the bottom of the front bowl's bottom rim. Or, midway along the front bowl bottom rim at the very front. This puts a common reference point relative to a part of a person's anatomy (the nose or the ears). As the ears have a centre point between them anyway I would favour the former.

Yes, that is what I had in mind. Each of the points of measurement is going to need a standard name, a taxonomy, and probably every point of the helmet should have one too, so there is no confusion over phrases.
The shape of the bowl needs a descriptor as well, the curve that is, since so many aren't parallel sided,and are more or less complete hemispheres.

Can you number those points on your chart? The points as well as the lines will have to have names.

Great stuff Jim!

I think that a plan view (top view) of the helmet would also be useful to determine the shape of the bowl (oval/round) and the shape and curvature of the brow guard if present.

Occipital ridges/steps is another important feature.

We now need to get all the Museums and private collectors to start getting out those (calibrated to a national/international standard) calipers to provide all the required information :? . This is the difficult bit!

Quote:The shape of the bowl needs a descriptor as well, the curve that is, since so many aren't parallel sided,and are more or less complete hemispheres.

I think that's pretty straighforward to be honest. If you took the top of the crown, and divided between there and the bottom front rim into 3 equal horizontal slices, measuring from the ear reference in two axes (front-to-back and side-to-side) on those dividers would give enough information to reconstruct the curvatures each way. If the curves' divider points are then given thresholds (+ or - this way or that way) you could come up with a subset of categories. This would allow for "vertical at the rim but steeply curves at section 2" to be given a simple name, with the possibility of adding an actual measurement + or - value. Co-ordinates, based on a common sub-origin on a general curve or semi-oval at pre-determined points.

The Y axis (that's Up to me, it's Z to others) needs no measurement as the height of the curve is determined by the height of the crown. The slices are equal subdivisions of the whole.

The semi-oval could continue at a tangent at its bottom rear end, which would give a measure for the occipital down to the neckguard, in all three axes.


Maybe? If that makes any sense? :?

Thanks Adrian :wink: Although I'm sure there are plenty of flaws in it.

What may be the best start would be to come up with a generalised averaged helmet shape. This gives all necessary co-ordinates, and then any common point on an actual artefact, or reconstruction of, is merely an offset (+ or-) of that co-ordinate.

I suspect the general terms of weisenau, hagenau and montefortino, et al, would still need to be somewhere in there, but all you do is come up with a standardised model for each, and that particular type is used for each case.

Quote:We now need to get all the Museums and private collectors to start getting out those ..

I agree entirely, which is why getting the methodology agreed upon and published, while it may take a while, will eventually get everyone doing the same thing.

Perhaps Dr. Bishop can give us some advice on this?

Rich, that sounds like a great idea. We did similar measurements for skulls in our archaeology lab at the University of Southern Maine. It would certainly make things a little more standard and hopefully less confusing.

While I'm lettering Tarbicus' drawing, I'll ask Gagan/Depeeka if that sort of measurement also suits what they need, if that's ok with you Tarbicus.

Go for it Rich, help yourself.

First thing, in addition to Tarbicus' measurements, is to agree on a breakdown on the metadata to describe a helmet. Here are my first thoughts:

Helmets can be described by three separate areas: bowl, cheekpieces, and neckguard. I separate the neckguard as it has its own geometry of curves, and the measurements will match up. Besides the measurements, the three areas have the following components (the list is a start: feel free to add in) and their attributes:

Bowl:
-browguard (material, shape, cutouts)
-browtrim (material, shape)
-earpiece (material, shape)
-crest holder (material, shape, fastening)
-crest tube (material, shape)
-rivets (material, shape)
-bosses (material, shape)
-trim (material, shape)
-decoration (material, shape)

Cheekpiece
-hinge (material, shape, fastening)
-rivets (material, shape)
-bosses (Material, shape)
-rings (material, shape)
-trim (material, shape, fastening)
-decoration (material, shape, fastening)

Neckguard
-carrying handle (material, shape)
-trim (material, shape, fastening)
-decoration (material, shape, fastening)
-rivets (material, shape)
-identification (name, word)

by fastening, I mean soldering or riveting
by identification as opposed to decoration, I mean the soldier's name punched or scratched into the metal. I wasn't aware that they could be on the bowl or cheekpiece, but that's easily added to the other descriptions.

Here's Tarbicus's proposed reference points again:
Helmet measurement points

Great stuff! Nice one Rich.

One question is, would this method be taken on board by the museums and archaeologists out there? One thing I thought of was that this could be published as an official paper so that it would have some credibility and allow for wider discussion.

Do you fancy proposing it for a paper? Publication in a recognised academic form is what really counts at the end of the day :wink:

You could outline the pitfalls of the current "guess-timation from photos" that goes on, which is far too subjective and can mislead in terms of actual comparisons and wild conclusions.

Its applications for reconstruction and analysis speak for themselves, especially if we get together a better idea of Roman head and body sizes which I've begun to look into, being pretty fed up of opinion and hearsay.

Quote:You could outline the pitfalls of the current "guess-timation from photos" that goes on

The answer to that is: find the original publications which, if sufficiently modern, will surely have archaeological drawings & measurements.
I'd go from the angle that the current typology is thoroughly confusing/outdated and needs renewal. However, to make a good typology you'd need to follow Rich's list through with all possible Roman helmets, stick them in a database and analyze results to see if they can be divided into various types.

Quote:find the original publications which, if sufficiently modern, will surely have archaeological drawings & measurements.

Unfortunately, there are publications that discuss gladii and spatha, and there are no references to length, and the diagrams have no scale reference to compare them to. :? I remember this from my attempts to find the shortest gladius. I suspect this could be the same with helmets, much of the dimensions coming from Robinson, et al anyway, including (I think, hence the request for Robinson's measurements) the measurements of the helmets in Militaria Sisciensia even though the helmets are right there in the museum (I don't speak Croatian so I don't know yet). However, once one single measurement is known and accurate drawings from plan views are available it's easy-peasy to do the rest, obviously. It really only needs a single measurement from one verfifiable known point to another.

I do have software that can be used to reconstruct a helmet in 3D from a series of photos, provided the format and lens are known and consistent throughout the photos. If a marker were used of a known length and in frame in the same place (on the glass?) for at least three of the photos, then the helmet could be virtually measured. However, if the back were not visible, for example, then that can't be reconstructed.