Roman crossbow

[Doc]

Robert Wimmers on this forum provided information on Roman crossbows. However, does anyone have an estimated blueprint with types of materials and measurements? Does anyone have an accurate reconstruction?

Thanks in advance.

[Flavivs Aetivs]

I have a few measurements I got from John Conyard of Comitatus, who told me about their superb arcuballista.

There's another late Roman group that made one, I'll let you know the name. Gimme a few minutes to dig up the info.

Off the top of my head though:

From the reconstructions I've seen (on the internet), the Bow is a self-bow (about 120 cm). and the stock is about 60cm long (including the handle). The grove for the bolt is also about 40cm long.

It's likely there was some system of proportioning like the Scorpio. Someone who knows more could tell you more. I've been looking to build one of these for a while now but have neither the time nor money ATM.

[Flavivs Aetivs]

From my Emails with John Conyard:

I fear size of the crossbow is conjectural since we only have iconography to go on. But common sense suggests the tiller would have to be made to match the power of the recurve bow you are using. Draw length should be matched to the bolts shown in iconography, but we cannot get any general agreement on that either. I went for a hunting style bow, others prefer a larger weapon.

This thread may be of help:

http://www.romanarmytalk.com/19-greek-mi...=15#341468

I put up a sort of basic steps on my website:

The late Romans invented the crossbow around the 3rd century AD, although they had been using a handheld version of the scorpio called a "manuballista" since the 2nd century AD. The Arcuballista wasn't exceptionally powerful, as it used wooden rather than Iron arms, but was easy to use and maintain. There have actually been 3 finds of Arcuballista parts, dating to the 5th and 6th centuries in Britain. Many of them were decorated on the sides with carved bone strips inserted into the stock. These also may have had some sort of effect when the bow fired, possibly stiffening the wood.


BASIC CONSTRUCTION:

The Arcuballista was an ash self-bow about 90-120cm in length, inserted into at least a 60 cm stock, with a 50cm grove for the bolt. At the back of the groove behind the bolt should be a bone or iron rolling nut, attached to a metal Z-bar, which acts as a trigger. The string should be natural rope or sinew, and bone nuts can only take so much draw weight, so it is recommended for higher draws you use an iron nut. The handle should be attached to the back of the stock.


An easier configuration is the sliding handle configuration, which has a flat nut on a pivot above the handle, that is kept from dropping by the insert of the handle into the wood. The handle is then pulled back, dropping the front of the nut and allowing the crossbow to fire.


- It is recommended a spring is mounted onto the Z-bar to reset the the firing mechanism, as we know the Romans used these all the time in doorknobs.

- The draw weight varies - do what is appropriate for you, but it shouldn't go above 80-90 pounds maximum.

- To span the crossbow, it is not spanned like a medieval one as that would break the arms. Instead place the arms perpendicular to you, with your legs spread on either side, with one hand on the handle and the other drawing the string. This is how you span the Arcuballista.

[Doc]

Hello Evan,

Thank you for the info. I appreciate it.

I am in the middle of making a squamata and have to finish a few other pieces. Once I clear them out, I will try and make a crossbow. There is a fellow who is getting rid of wood and he told me that I can take what I like. Being this is on my to do list, I wanted some info so I can see how much wood I need.

Cheers

[Flavivs Aetivs]

Yeah. My estimates are rough - if it looks aesthetically pleasing, you probably did it right.

[Thomas V.]

BASIC CONSTRUCTION:

The Arcuballista was an ash self-bow about 90-120cm in length, inserted into at least a 60 cm stock, with a 50cm grove for the bolt. At the back of the groove behind the bolt should be a bone or iron rolling nut, attached to a metal Z-bar, which acts as a trigger. The string should be natural rope or sinew, and bone nuts can only take so much draw weight, so it is recommended for higher draws you use an iron nut. The handle should be attached to the back of the stock.


An easier configuration is the sliding handle configuration, which has a flat nut on a pivot above the handle, that is kept from dropping by the insert of the handle into the wood. The handle is then pulled back, dropping the front of the nut and allowing the crossbow to fire.


- It is recommended a spring is mounted onto the Z-bar to reset the the firing mechanism, as we know the Romans used these all the time in doorknobs.

- The draw weight varies - do what is appropriate for you, but it shouldn't go above 80-90 pounds maximum.

- To span the crossbow, it is not spanned like a medieval one as that would break the arms. Instead place the arms perpendicular to you, with your legs spread on either side, with one hand on the handle and the other drawing the string. This is how you span the Arcuballista.

The bow ("prod")

We don't know if the arcuballista prod was a self bow. Composite prods would be another possibility. If you use a self bow, yew would be a better option, as it was THE bow wood and as the all-wood prods I know of were made of yew. Speaking of all-wood crossbow prods: The shortest one I know of, is c. 90 cm long (Skane, 16th century); the longest one I know of is c. 120 cm long (Berkhamsted; early 13th century). So regarding self bows, your measurements are a good choice. The draw length of the crossbow from Skane is about one third of the lenght of the prod. This proportion can be used to determine the draw lenght of (rather) short all-wood prods.

The nut

The nut should be antler or bone. The only iron nuts I know of, belong to crossbow traps that are dated much later. And: If you use a nut socket, an iron nut might be to heavy.

The trigger

As the nuts that might be an arcuballista part don't have an iron reinforcement, an iron trigger would be to hard. A trigger constructed like the ones used with unreinforced antler (or bone?) nuts (two antler or bone scales, riveted together by bone pins [antler scales], copper-alloy pins [bone scales] or iron pins [antler scales]) would be a better choice.

According to Josef Alm, trigger-resetting springs weren't used before the 15th century.

There are no hints for the slider mechanism.

Stock, handle and proportions

60 cm (excluding the handle) seems to be a good choice. Just have a look at the forearm-stock ratio shown in this relief: [hide]http://www.jaanmarss.planet.ee/juhendid/Kaugrelvad_Antiik-Roomas/andmebaas/album_arcuballista/album_HTML/images/034_1.jpg[/hide] The stock is about as half as long as the prod; maybe another indicator that a prod length of c.120 cm is a good guess ;-).

By using the the length of the stock and the handle-stock ratio shown in the two famous reliefs, you can determine the length of the handle. IMO 1:4 is a good choice.

Assuming that the stock is 60 cm long, the overall-lengt would be 75 cm. If the prod was 120 cm long, the prod-"stock plus handle" ratio would be about 3:2. Said ratio also exists in the case of the famous Moorish Granada crossbow, wich is, according to Richter, influenced by Roman crossbows.

[Martin Moser]

HI Evan,

The late Romans invented the crossbow around the 3rd century AD, although they had been using a handheld version of the scorpio called a "manuballista" since the 2nd century AD. The Arcuballista wasn't exceptionally powerful, as it used wooden rather than Iron arms, but was easy to use and maintain. There have actually been 3 finds of Arcuballista parts, dating to the 5th and 6th centuries in Britain. Many of them were decorated on the sides with carved bone strips inserted into the stock.

Do you have a bibliopraphical reference for any of those finds for me perhaps? Thanks in advance!

[Thomas V.]

@Martin Moser

Goddard, E H 1896 'Notes on a Roman Cross-bow, &c., found at Southgrove Farm, Burbage'. Wiltshire Archaeol Nat Hist Mag, 28 (1894-6), 87-90.

Crossbow nut and parts that might have belonged to the crossbow: [hide]http://archive.org/stream/wiltshirearchaeo28arch#page/86/mode/2up[/hide]. It is also dated to the 8th or 9th century.


MacGregor, Arthur 1978 `Two antler crossbow nuts and some notes on the early development of the crossbow' Proc Soc Antiq Scotl 107, 1975-6 (1978) 317-21, fig, refs. []

A crossbow nut that might stem from the Roman period: [hide]http://archaeologydataservice.ac.uk/archives/archiveDownload?t=arch-352-1/dissemination/pdf/vol_107/107_317_321.pdf[/hide].

[Eleatic Guest]

The only two certain pictorial representations I am aware of: http://commons.wikimedia.org/wiki/Catego..._crossbows

[Flavivs Aetivs]

The bow ("prod")

We don't know if the arcuballista prod was a self bow. Composite prods would be another possibility. If you use a self bow, yew would be a better option, as it was THE bow wood and as the all-wood prods I know of were made of yew. Speaking of all-wood crossbow prods: The shortest one I know of, is c. 90 cm long (Skane, 16th century); the longest one I know of is c. 120 cm long (Berkhamstead; early 13th century). So regarding self bows, your measurements are a good choice. The draw length of the crossbow from Skane is about one third of the lenght of the prod. This proportion can be used to determine the draw lenght of (rather) short all-wood prods.

A self bow seemed to be the most reasonable choice to me, considering the climate they have been found in (a composite bow would have been harder to maintain.) I agree that some may have been Composite bows. In terms of wood, I chose ash because Yew isn't exactly cheap, but yes it is a better choice.

The nut

The nut should be antler or bone. The only iron nuts I know of, belong to crossbow traps that are dated much later. And: If you use a nut socket, an iron nut might be to heavy.

True, Robert Wimmers mentioned bone might not be able to take higher draw weights.

The trigger

As the nuts that might be an arcuballista part don't have an iron reinforcement, an iron trigger would be to hard. A trigger constructed like the ones used with unreinforced antler (or bone?) nuts (two antler or bone scales, riveted together by bone pins [antler scales], copper-alloy pins [bone scales] or iron pins [antler scales]) would be a better choice.

According to Josef Alm, trigger-resetting springs weren't used before the 15th century.

There are no hints for the slider mechanism.

The spring reset was on Robert Wimmer's suggestion. I mention an iron trigger because no bone/antler triggers have survived, where all the bone/antler nuts have survived. An interesting conundrum.

The fact that no triggers survive suggests maybe the sliding handle mechanism, especially considering that at least one of the surviving nuts I know of are flat.

Stock, handle and proportions

60 cm (excluding the handle) seems to be a good choice. Just have a look at the forearm-stock ratio shown in this relief: [hide]http://www.jaanmarss.planet.ee/juhendid/Kaugrelvad_Antiik-Roomas/andmebaas/album_arcuballista/album_HTML/images/034_1.jpg[/hide] The stock is about as half as long as the prod; maybe another indicator that a prod length of c.120 cm is a good guess ;-).

By using the the length of the stock and the handle-stock ratio shown in the two famous reliefs, you can determine the length of the handle. IMO 1:4 is a good choice.

Assuming that the stock is 60 cm long, the overall-lengt would be 75 cm. If the prod was 120 cm long, the prod-"stock plus handle" ratio would be about 3:2. Said ratio also exists in the case of the famous Moorish Granada crossbow, wich is, according to Richter, influenced by Roman crossbows.

What can I say, I'm a good guesser. If you have images of the moorish Granada Crossbow, I would be interested in them.

As for the sources you and Eleactic Guest linked to, those are the ones I used. The Wiltcheshire Farm nut is the earliest crossbow find, dating to approximately 500 AD.

[Thomas V.]

If you have images of the moorish Granada Crossbow, I would be interested in them.

Here you go: [hide]http://chestofbooks.com/arts/ancient/Older-Spain-Arts-And-Crafts/images/Moorish-Crossbow-And-Stirrup-Museum-of-Granada.jpg[/hide]

[Flavivs Aetivs]

Great! Although I'd go with the reconstruction of a thinner bow by other groups myself. That seems more like a 2x4 in a wooden stock.

[Thomas V.]

Great! Although I'd go with the reconstruction of a thinner bow by other groups myself. That seems more like a 2x4 in a wooden stock.

Yeah, it' realy clumsy. But it's of almost the same length as [hide]the prod from Berkhamsted.[/hide]

[Eleatic Guest]

Monograph: Dietwulf Baatz - Die römische Jagdarmbrust
Encyclopedic entry: Le Dictionnaire des Antiquités Grecques et Romaines de Daremberg et Saglio - Arcuballista, manuballista

[Flavivs Aetivs]

The first link gives me a malicious pop-up, just to warn you.