hold the ring

Probably from keep the ring. In days past when spectators would encircle participants in a prizefight or a performance, people would be employed to maintain order among them and keep them from coming too near the participants.

• "Police held the ring during the protests."
• "In England a century earlier it had been a struggle between two warring houses, in France it was now a struggle between three: Guise, Montmorency and Bourbon, with the feeble government of Catherine de Medici vainly trying to hold the ring."
• "While this debate was going on in Nature another was being conduct in Archaeometry. This was between Betancourt – and his old colleague Michael – and Warren, with the English archaeometrist M. J. Aitken holding the ring."
• "It is the great powers that create international upheavals. In 1912–13 the Balkan powers fought two bitter wars among themselves, while the great powers held the ring."
• "Lieutenant-General Fry says that coalition forces will continue military operations "to separate the two sides of the sectarian conflict" but that such operations were meant to hold the ring until the politicians come up with a solution."