This is going to be a collaborative TL, the first event being in the year 400 AD. Dont make ASB events, and if you do, by a concesus, we can retcon it. For now, only events from 400-420 are allowed.
400 AD- Franks establish themselves in the north of the Netherlands.
401 AD- Kumarajiva, a Buddhist monk decides to head west to bring Buddhism there.
403 AD- Kumarajiva arrives in Constantinople, and begins to convert.