Example: early Gunpowder means you're the only one that can roll 'Guns/Butter' event.
And early IW means you are likely to roll Elite Swords quest? BTW, it is said here https://forums.civfanatics.com/threads/random-events-list.236727/#post-5789100 that it requires state religion, but I had no state religion. I did have Buddhism in Rome, though. Apparently this information is not entirely accurate, probably not up to date.
Edit: That game is very promising, probably good enough to beat 460AD Culture record. There is a problem with AI's research rate: it's pathetic, even Mansa is useless. On the other hand, I can reserve the Oracle for Biology, something I had difficulties with even on Tiny (and this is Small!). Or should I use it on Currency