I'm curious about the very early Christianity and how it spread across the Roman Empire. The specific timeframe would be between Jesus and Julian - so the first ~350 years.

My specific question is that Jews were a small subset in mostly one country in the Empire and although some Jews converted initially, my real question is how and why Roman non-Jews converted and how it spread all the way to the Emperor in a few centuries.

Bonus: if you have any recommended links, videos, or books that you believe would be helpful (to an amateur like myself), those would also be appreciated.

Thanks in advance!