Making a (first century AD) tunic

[Marcus Hortensius Castus]

True, and you are not alone in that opinion, which could well be true. However, that said, woollen clothing has always been in widespread use in the Mediterranean and I have always been led to believe that it forms the usual material for most traditional North African clothing. Sometimes it is not so much a case of what you wear as how you wear it. Woollen cloth can insulate you from the heat as well as the cold.

Crispvs

Also don't forget wool has cooling qualities when damp, so the sweat of the soldiers would have dampened the tunics and as it evaporated the legionaries would have been cooled. When I was younger I had a WW2 Britihs canteen covered in wool, and inquired as to why it was covered in wool; I tried it out and sure enough, on a warm or hot day, if I dampened the wool cover the water inside was pleasantly cool.