There were a few hundred kohanim gedolim in the second bais hamikdosh many of whom died on 'the job' on yom kippur in the holy of holies. Knowing this, what induced them to become a kohen godol which ...
I don't know if they are technically called "piyutim", but there is a nusach we say on Rosh Hashana/Yom Kippur between "Ata Kadosh" to "Hamelech Hakadosh". Was that decreed by the Anshei Knesses ...
It's commonly believed that the "ten martyrs" didn't all live in the same time period, and the description of them as a group is conceptual, not historical. Now the story opens with a Roman ruler ...