TIL when I read in books about people eating a "joint of mutton" in the medieval and early modern period that I had the idea all wrong. I imagined a leg bone with meat on it...you know, bone, joint.
But no. Roasting mutton by fire is hard if you leave the bones in because bone insulates against heat pretty well.
So it was typical to debone the mutton and roll it back up tightly before roasting it; if done right, it looked like a leg.
"Rolling a joint" is a much older term than I thought.