Where I've looked: "history of Oxford" "history of Cambridge" "founding Cambridge University" "scholars leaving Oxford" etc.
1. Both Wiki and the history pages of the two colleges hint at some sort of violence between students and townsfolk, circa 1209, that made the scholars and students leave Oxford and head to nearby Cambridge. They also talk about some resentment between townspeople overcharging students for rent and food, and students getting up to "boyish hijinks" like rape. It wasn't a totally happy arrangement, but I can't seem to find the final incident that made them pack up and leave. I did find a clue of a "three day riot" but not what the riot was about.
2. Obviously, some scholars did go back to Oxford and re-establish the university there. Slow trickle? Tired of Cambridge? I can't seem to find a date or reason for this either.
And some basic questions about early scholastic life:
3. It seems like students paid for their food and lodging, but not for instruction. How does that work? Where do the professors get their money to pay their food and lodging?
4. When did the dormitories get set up? It seems like they are later than my period, and these early students would have been living in boarding houses or renting rooms from families?
5a. What did students call their teachers? Professor? Doctor? First Name? Surname?
5b. What did teachers call their students? First Name? Surname?
6. It looks like the main topics of study were religious philosophy and medicine. What else?
7. When they left Oxford, why did they pick Cambridge? Was it just distance, or was there something else?