Possible Clues:

• Hand-to-hand combat?
• Fighting with punches
• Physical coming-together? Duke is accepting restraint on movement
• Dispute involving a number of dukes
• Bare-knuckle combat
• Providing revolutionary, bodies trapping copper fight
• If reflected bodies contain copper, the result is violence
• Fighting with dukes?
• Scrap copper collected by motor-sport bodies
• Pugilism