In a post as closely relevant to current affairs as you're ever likely to see on this blog, I thought I'd mention that the job title Pontifex Maximus, better known these days by the shorter form Pope, is far older than the Roman Catholic Church. The most famous pre-Christian holder of the office was a chap by the name of Julius Caesar.
It was because Caesar was Pontifex Maximus that he was able to reform the calendar. (Since in Rome the Pontiff owned the calendar, like the Eponymous Archon did in Athens).
The rule most interesting to a mystery writer though is that the original Pontifex Maximus was forbidden to see any dead body.