Neil Lucock

http://en.wikipedia.org/wiki/Sarcina

Trajan's column shows legionaries with their marching packs over their shoulders. One of the items hung from the furca (a cross shaped carrying pole) is what appears to be a simple sack.

This is a quick easy project.

Equipment needed;
Leather (24 inches x 24 inches plus some for straps.)
Thongs and/or linen thread
An awl and tools to cut the leather with.
Needles.
A Ruler or tape.

Construction

 

I made my sarcina from a piece of leather 24 inches by 24 inches (60 cm by 60 cm)
You work inside-out. Fold the leather in half. Sew along one long edge and one short side.
 

You can sew it using either linen thread or leather thong. For this you need special needles. These are made from two pieces of sprung steel with a hole in one piece and teeth that fit through the hole. The teeth grip the leather. Taper the end of the thong to the width of the needle (otherwise it will never pass through the hole in the leather you are working on). Prise the two ends of the needle apart, put the end of your leather thong in and hit it (I use the hilt of a knife). This grips the thong tightly and attaches it to the needle.

Once you have sewn up one long and one short side, it looks like this:
 

Turn it the right way around so the good face of the leather faces out.
You need a drawstring. Use a long piece of thong. Make some holes 4 inches (10 cm) from the open edge of your bag. I made 5 pairs around the mouth of the sack. Thread the thong through and put a knot in each end to prevent it coming out.

The sewn edge of the sack should be at the bottom when it hangs from your furca (to help keep rain out). Make two attachment straps, they should be 6 inches by one inch (15 cm by 25 mm). Sew one near the closed end, one 7 inches (18 cm) from the mouth.
 

Treat with waterproofing, put a spare tunic or cloak in to give it shape and it's done.