Good read, but are we willing to call this the first self-insert?
Hear me out, it's 1472, you're a devout christian and you set to the idea of hell and writing of it. What do you do? You write up a really dedicated piece of fanfic about how Dante, your favorite, accepted you into his squad and you had a great time together as you hung out with him and all his buddies. You're all like "My fave Dante, who's like super cool, was there and we were the bestest of friends as we went through hell".
In closing, when a 13 year old girl writes self insert fanfic to mlp or something she's super cringey, but when Dante Alighieri writes self insert fanfic it "Redefines the way we look at christianity" and "is a classic". The double standard.