In Pierre Barbet’s book, A Doctor At Calvary we find this description:
"… a distinctively Roman instrument was used.; the flagrum. It had a short
handle, to which were attached several long, thick thongs, usually two of them.
At a little distance from the end balls of lead or the small bones of sheep were
inserted… The thongs would cut the skin and the balls and the little bones would
dig deep contused wounds into it. There would be a great deal of hemorrhage
and considerable lowering of vital resistance."