You may or may not know about the practice of instauratio. Roman rituals required a perfect performance first time, or they would have to be repeated from the beginning – this was the case even for theatrical performaces at the ludi (games). I have just come across a passage from Servius explaining a Roman proverb originating from the Second Punic War:
Finally, when the circus games for Apollo were being celebrated and it was reported that Hannibal was attacking the city near the Colline Gate, everyone grabbed their weapons and ran there. Later, when they returned and were concerned about the necessary sacrifice, they found a certain old man dancing in the circus. When asked, he told them that he had not stopped dancing, and so the proverb goes: ‘All is well, the old man is dancing.’ [salva res est, saltat senex.]
In this particular instance, because of the good old fashioned Roman nerve (and presumably stamina) of the old man in continuing the ritual alone, there was no need to repeat it with the necessary sacrifice to appease the offended Apollo. Huzzah.
One scholar comments that, given the large number of insturationes recorded by Livy between 216 and 179, it ‘makes one almost suspect instaurationes were used as a poly to extend the length of a dramatic run’!