I went to a cheese lecture a long time ago and I remember being told that one kind of cheese was eaten by the Roman Army. The lecturer showed a modern example of the cheese, and explained how the Romans wrapped it in black wax and hung it on a rope to make it easy to carry and long term-storage friendly. It was ball shaped, so looked like a small cannon ball.

I can't find any description of this on Google no matter what keywords I use - what am I remembering and how DID Roman soldiers carry their cheese ration?