​Diamond twills are one of the textiles highly coveted by Viking Age reenactors today.  However, what is, and what isn’t, a period diamond twill is not as readily understood.  To better explain the difference in the types of diamonds we can buy today, I am going to start with a bit of information on weaving.
 
The most basic weave is called Tabby weave.  It is also sometimes called “canvas weave” or even “linen weave” despite that it could be crafted from any type of fibre.  The description of “linen weave” is wonderfully accurate, because most linens, even today, are of the simplest weave structure.  In this weave, each thread of the weft (the yarn that runs across the fabric from selvedge to selvedge) crosses over one warp (the threads that run the length of the cloth) and then under the next.
 
Tabby is one of the most common weaves in the Viking Age.  For most regions, you really cannot go wrong with tabby in a solid color.
 

​The other popular weave in the Viking Age is a 2/2 twill.  Twill textiles have a weave structure that has a visible diagonal line.  Think of denim and it can help you picture this.
 
In a 2/2 twill, the first weft thread passes over two warps, then under two, then over the next two to the end of the line.  The next row will be offset.  Again, for most regions, you cannot go wrong with a basic twill in a solid color.
 
There are, of course, many other types of weaves in the period, even if they are not as popular as the two mentioned above.  These include 2/1 twill, herringbone twill, cross twill, lozenge and diamond twills.  It is the last two that I want to discuss at this time.
 
We run into a couple of issues with obfuscation between the terms Diamond Twill and Lozenge Twill.  This is partly because there is no one set of naming conventions for weaving, and also partly because people do not readily recognize the difference in the two and misuse the terms.

First, look at the weaving diagrams for three types of this group:

​2/1 “Lozenge or Diamond Twill”, 2/2 “Lozenge Twill”, and “2/2 Diamond Twill” (which I also call “Broken Diamond Twill” to help make the distinction more clear).  Sometimes you will see Lozenge Twill replaced with Birds-Eye or Goose-Eye Twill.  Lise Bender Jørgensen, one of the top experts in early textiles of Northern Europe, typically makes the distinction between Lozenge for unbroken-diamond twill and Diamond for the “broken” variety, for the 2/2 types, but even she refers to the 2/1 pattern as either.  How confusing is that?  She explains further the choices in another volume, but the details are very weaving specific and I am not going to cover them here, especially because these terms can change from writer to writer or weaver to weaver. 

What do I mean by “broken”?  In the Broken Diamond Twills, you can see that the pattern counterchanges, and the diamond in the center is not a solid color.  That shift is what I am calling a “break”.  The Lozenge Twills do not have that, and appear to be one diamond set atop another.
 
To make all of this more confusing, not every Broken Diamond Twill looks exactly the same.  There are slight variations in size and repeat of the patter, but the key is that they all display that distinctive “break” in the pattern.
 
So why is this important?  It is important to understand the difference because in the Viking Age, the Diamond Twills that we see are almost always of the “Broken” variety.  Knowing the difference, and being able to “read” the cloth, allows us to make our best choices when spending money for textiles, or taking the time to weave our own.

​At York, Denmark and in Norway we only see Broken Diamond twills.  At Sweden we see the same, with the exception being Birka, where we see 8 three-shaft Lozenge Twills (Broken Diamond and 2/2 twill are woven with 4 shafts).  8 textiles out of thousands were truly Lozenge Twills rather than Broken-Diamond Twill.​

Even more important, is that all of these examples of Lozenge Twill were of the same type.  These were delicate, almost sheer, and of a very high thread-count (50-60 threads per cm).  Further they were smooth, shiny and no trace of “wooliness”.  They were dyed so dark with woad that they were almost black. (Geijer, Birka iii, p26-27).  There was one more fabric of this quality/color that as well that was also a 3 shaft twill.
 
If you want more weaving-nerdy-info, please see this article by Hrolf Verberg that helps to explain why the 2/2 twills are of the Broken variety.  And if you are curious about percentages of weaves at various sites, you can see my charts HERE.  Some of my handwoven examples are below (the top-right one uses two colors to better show the weave).

​This is a complicated question.  Ideally, if you were in a serious reenactment group, or if you were taking the time to weave the cloth yourself, you absolutely would want to choose the Broken Diamond Twills for your kit if you were representing someone from anywhere other than Birka.  If you are looking at Birka, you would want to look more closely at the graves with that special type of Lozenge Twill and take a closer look at the context, and try to find a very fine cloth that matches that specific type to get the most accurate representation possible.
 
And for anyone else?  I would still recommend that if you are laying out a great deal of money for specialty cloth that you look for the “correct” thing first.  That is not to say that I would not purchase a Lozenge Twill if the price was right or if I really wanted something in linen for Pennsic and I could not find a Broken Diamond Twill.  Also, never pass up a good bargain on wool when you can find it!  And, in the SCA especially, we often make concessions for things like opting for the not-quite-perfect-but-close fabric because it is what we have access to (please note the difference in your documentation if it is for a competition though).  For example, you might really need a dress for an elevation and want to use the red from your heraldry and the only cloth available is Lozenge Twill, well, go for it!  If you already have a garment in Lozenge Twill?  Don’t sweat it!  Wear it with pride.  From any distance it is almost impossible to tell apart!
 

• Saxon textiles were also of the Broken Diamond Twill type
• For the Viking Age look for solid colors when possible, or at least colors that are close together.  Solid Red, Brown or Blue would be stellar, and I would look at something like Dark Brown warp with Light Brown weft as quite decent as well.  I would avoid purchasing a cloth that has drastically different colors in the two systems if I were aiming for a very accurate garment, unless I found a bargain I could not pass up (and even then, I might overdye it at some point).
• Look for SMALL diamonds.  The existing textiles, even where we think they belonged to a cloak, were not large.  Some of the textiles had diamonds that were smaller than a centimeter tall!  I would not buy anything with diamonds over an inch, and even that I would think twice about, especially for a garment like a tunic or aprondress.
• We do have two examples of Broken Diamon Twill linen, both from women’s clothing. (see article HERE).
• Remember, you can never, ever go wrong with plain Tabby or 2/2 Twill in solid colors, EVEN for a very high status persona!

 
Some options for purchasing Broken Diamond Twills are below (I will update this as I get more recommendations):
 
Woolsome: Note that the linens, wool thin diamonds and wool/linen mixes are Lozenge Twills, not Broken Diamond Twills.  The Handwoven Diamonds are Broken Diamond Twill.
https://www.woolsome.shop/
 
Classic Fabrics: This site also carries both types, look very carefully at the weave when selecting.
https://classicfabrics.nl/category/fabrics/wool/?filter_weave=diamond-twill
 
TheHistoricalFabricStore: I _think_ these are all Broken Diamond, but one might want to clarify before ordering. The diamonds are SMALL and these are in solid colors so even if these were lozenge twills, I would be tempted regardless.
https://www.thehistoricalfabricstore.com/diamondtwill
 
Der Stoff Dealer: Sometimes has Broken Diamond Twill
https://www.der-stoffdealer.de/
 
REFERENCES

Bender Jørgensen, Lise.  Northern European Textiles until AD 1000, Aarhus University Press), 1992.
 
Bender Jørgensen, Lise.  Prehistoric Scandinavian Textiles, (Det Kongelige Nordiske oldskriftselskab), 1986.
 
Geijer, Agnes.  Birka III, Die Textilefunde aus Den Grabern.  Uppsala,1938.
 
Hägg, Inga. Textilien und Tracht in Haithabu und Schleswig, Wachholtz Murmann Publishers, 2015.
 
Walton Rogers, P.  Textiles, Cordage and Raw Fiber from 16-22 Coppergate, The Archaeology of York Volume 17: The Small Finds. 1989.
 
Walton Rogers, P.  Textile Production at 16-22 Coppergate, The Archaeology of York Volume 17: The Small Finds.  1997.

The article has been published in the Archaeological Textiles Review for the Lendbreen constructions.  I love that the time needed to reconstruct the garments was included, as it is very important for providing context for the garments.  (Yes, I also love that they used Villsau wool!)

https://www.academia.edu/35628286/Reconstructing_the_Tunic_from_Lendbreen_in_Norway._Archaeological_Textiles_Review_no._59_2017_p._24-33_SFA_Center_of_Textile_Research_Copenhagen

Recently on the Viking Clothing forum on Facebook (the rather "hardcore" forum I have mentioned before in some of my posts), there was a discussion about necklines on women's Viking Age caftans/coats.  Quite often I see coats with a very deep U shaped cut out.  There is no real evidence for that cut, though I do understand why reenactors opt for that shaping.  It allows for one to see the impressive brooches and bling.  

There is some scant evidence of a straight edge opening, so when I made my own coat, I opted for something between the two.  I choose a deep V neck that has only the very slightest curve to it.  Unfortunately, my entire coat came out too large, so that neckline opens up too much and the whole thing wants to slide off my shoulders.  (Fortunately, I already have cloth with which to craft a new outergarment at some point.)

I think the most brilliant reconstruction I have seen so far is offered by a reenactor named Louise Archer.  She gave me permission to share her work here.  Her coat is which is made from a Herdwick diamondtwill wool and in her detail photos you can see she has a Dublin scarf.  That is made from Manx Loghtan wool!  (I cannot express how much I love her choices, and how lucky I think she is to find these wools to work with.) Her coat comes to the neckline, as would a straight-opening male caftan.  She can fasten it at the top for warmth, OR just use the brooch further down, which allows it to open at the top around her brooches and bling.  This is practical the similarities to the proposed male garment make it make a great deal of sense.  Beyond that, this construction (or anything with a straight edged front) also makes it somewhat similar to items from nearby cultures (such as Frankish or Saxon women's coats).

Beyond her wonderful coat, I also wanted to point out the photo of her Dublin style cap.  This very will illustrates one of the points I made a few days ago in my article on the facts we have about headcoverings from the Viking Age (that being that all of the extant examples are actually very, very tiny).

I really love this work and look forward to seeing more from Louise.

(Note If you bring up wool to many people, especially in America, and the first thing they think of is the itchy sweater that their grandmother knit for them (mine was red).  These memories can often make people shy away from wool fabric for reenacting purposes, but the reality is that for most of us, that would have been the choice material for our persona.  In fact, some very strict groups have requirements that state you have to make your garments out of wool to even participate.  Inevitably, this brings up the conversation about someone's wool allergies and what to do about that.

First thing that needs to be understood is that no one is actually allergic to wool itself, unless, of course one is also allergic to the hair on their own head.  Wool is made of keratin, just like our own hair and finger nails.  There are, however, some people who have reactions to it, so understanding the actual cause of the reaction is important.  

• Scouring Agents:  When wool is processed it is "Scoured".  This is removes the lanolin (the natural oil of the sheep) before spinning.  Historically, this could be done with a variety of methods, including something as simple as repeated soaking in hot water.  In modern cloth, they use harsh chemicals to manage this work.  Some of the chemicals might be left in the material, which can cause reactions.
• Lanolin: As mentioned before, lanolin is a wax secreted by glands of the sheep.  It helps water to be shed from the wool and also helps protect the animal's skin.  Not all scouring processes remove every bit of lanolin, so it is possible to have a reaction to lanolin if you are sensitive to it.  
• Sizing: This is a chemical that is added after the cloth is made, to help best present it for commercial display.  This can also cause allergic reactions.  I know someone who will get puffy red hands after handling some types of cloth in a fabric store or even clothes hanging on racks in retail stores.
• Dye: Occasionally certain fabric dyes might cause sensitivity in some individuals.

If your reaction is caused by one of these, it might be possible to remove the problem by careful washing of your cloth.  Dharma Trading (as well as other outlets) sell detergents such as Synthrapol which is specifically designed to remove chemicals, excess dye, oils, etc, from fabrics or fibers.  While this is specifically used before dying cloth to make sure that the color takes well, it can also be used to try to remove other chemicals as well.

http://www.dharmatrading.com/chemicals/synthrapol-detergent.html

There is one other factor, and likely it is the most common one, that can make people shy away from wool.  That is the "scratchiness" of the fiber itself.  This reaction can be excessively annoying and can happen for a couple of reasons.

• Coarseness:  The wool itself might be of a low quality and thick.  The wool fiber is covered with fine, overlapping scales.  Coarse wool has more coarse scales, while fine wool has scales that lay more flat.  The former can be more irritating.
• Spinning: If yarn is loosely spun, there might be hairs that escape the shaft of the yarn and that poke out.  This creates a fuzzy look that we often associate with woolens, but these individual fibers might irritate sensitive skin in some people.

My suggestion is to test out different wools.  Look for Merino wool, which is exceptionally fine and has very fine scales.  Many people that normally dislike wool can still wear a very soft merino sweater.  Another option is to look for worsted wools.  This process of spinning keeps the hairs aligned in the shaft of the yarn, with no fuzzy bits sticking it.  It produces a very fine, smooth cloth which is quite period for many reenactors.  Some times this will be listed as "worsted" cloth, but most men's suiting wools can be in this category as well.

Also look for a more fine cloth.  Some vendors, such as Burnley & Trowbridge, sell swatch sets of their cloth.  I recommend ordering swatches from them and other outlets to see which materials might best suit your needs an level of sensitivity.  There are 100% wool fabrics out there that surprisingly don't actually "feel" like wool at all.

Another factor that comes into play is the perception that all wool will be hot and heavy.  Much of the cloth from Norse finds is exceptionally fine with very high thread counts.   They had lightweight wools!  As mentioned above, poke around online and order swatches to see the variety of cloth that really exists.  I prefer wool for my veils and headdresses.  A wool gauze is no warmer in the summer than linen and my handwoven wool dress is no warmer than a linen of the same weight.  Avoid coatings or heavily fulled materials if heat is a concern.

Another option, for those that do not have a chemical sensitivity, or who can wash out the offending chemicals, but still find wool uncomfortable, is to make sure that the wool fabric does not touch the more sensitive areas of your body, such as your neck.  For women doing Viking age, this can be simple as you can wear a wool aprondress over a linen underdress.  However, if you need a wool tunic you can wear a wool one over linen and then you can add a linen facing inside the neckline and inside the sleeves to prevent the wool from coming in contact with your skin.  Tacking it down on the inside with small stitches will leave it invisible from the outside completely and adding a wear cord at the opening edge will further remove it from your skin.

(Note that this post is not an insistence everyone wear wool, but I do know many people who previously shied away from the fibre by working with it and figuring out how to make it work for them.  As always, your own best comfort is important so be reasonable as you test your limits!)