The bag is constructed after the almost complete find from an Augustean shipwreck on the coast of Italy, near Comacchio, and measures about 30 x 29 x 7 cm.
I chose veg-tanned sheeps leather for the bag as the original is reported to have a leather thickness of 1mm only (the report does not specify what animal the leather is from). The teardrop-shaped applications were dyed with a vinegar/iron dust mixture, then treated with neatsfoot oil. While this may or may not actually have been used by the Romans to produce black leather, it would have certainly been in their range of possibilities and since I do not know of ancient leather color-dyeing methods I tried that one.
All measures are calculated from the data and drawing of the publication so hopefully are somewhat close to the original.
First you need the leather parts, 1 rectangle 82 x 29 cm, 2 rectangles 39 x 7 cm.
The 2 rectangles forming the sides are 9 cm longer than the bag is high, this 9 cm bit is folded over inwards (probably for strengthening), taking up the shoulder strap.
The large rectangle is the bags body, sectioned as follows:
30 cm = front
7 cm = bottom
30 cm = back
15 cm = flap
Preparing the drop shaped applications:
I decided to dye those bits black for contrast. From the original nothing more is mentioned in the find report than that they are drop-shaped (only 2 of the 4 are still existing and in place). Size is about 4.5 cm high by 3.5 cm wide.
For dyeing I use a mix of vinegar and iron dust (very fine steel-wool also works well). Normally I do the dyeing twice for intensity, then after drying oil the leather with neatsfoot oil. This deepens the up to then somewhat grayish black and gives the leather its flexibility back.
The picture shows the various stages, the form of one of the applications can be seen marked out with pencil.
Sewing on the drop-shaped applications:
Placement (measured from the hole in the applications where the strings for tying the bag come through):
-the pair on the front should be placed at about 9.5 cm inwards from the sides and about 11cm downwards from the upper edge
-the pair on the flap should be placed ar about 9.5 cm inwards from the sides and about 3 cm upwards from the end of the flap
Probably not really worth mentioning , but as the stitch marks show, the pieces were sewn on all around along the edge.
Putting in the side pieces: I marked and pierced the holes on the long sides of the main and side piece starting at the same distance from the edge and at the same interval. On the short side of
the side piece I moved the outer hole to the left and the right a bit towards the middle to account for the 90 degree bend. I did almost the hole of the U-shaped seam with one long piece of waxed
linnen thread starting on the front top edge. Only the last 5 holes or so were done against that direction in order to be able to hide the knots a bit deeper down and inside the bag.
In order to get a nice and even seam follow all the time the same in-out sequence with the yarn. By piercing the holes with an awl and widening them enough that way, you don't even need needles or anything to sew. Just simply thin out the ends of the waxed yarn and twist them tight again to form nicely drawn out, thin tips.
The edging - stitch marks at the sides and end of the flap as well as on the upper end of the front part imply that there may have been edging of some sort. I use a strip of thin deer leather 1.5 cm broad. Holes are at 6mm distance again, 3mm from the edge (thats for both the edging leather strip and the parts of the bag itself.
Preparing the upper end of the side pieces for the shoulder strap: These are folded over backwards, probably to strenghten that part, and show a slit, taking up the shoulder strap, ca. 2cm wide and at about 1.5 - 2cm downwards from the top edge.
I decided to incorporate the folded back part of the side pieces into the seam joining the side and main pieces of the bag. this meant opening that seam once more, as I hadn't thought about that early enough :-P
There may or may not have been edging around the protruding part, we don't know. I went against it, as the leather is doubled here already anyway.
We also don't know anything about the shoulder strap, as that piece is missing. All that remains, it seems, is part of how the strap was held in place at the side pieces. Unfortunately though, the description is rather brief and there is no drawing of it either. Because of that I decided to go with a simple strap, going in at the slits of the side pieces and fastend with a seam following the form of the remaining stitch marks.
The last thing left to do is inserting the leather laces used to tie the bag closed. With the original, only the upper pair is still existing, and they are around 35-40 cm long, secured from behind with a simple knot.