Hold a BA from OxBridge? Can have a MA after a few years!

Due to the ancient tradition, students who have earned Bachelor of Arts (BA) degrees
from the medieval universities such as Oxford and Cambridge are entitled to receive
Master of Arts (MA) title a few years after graduation without sitting assessments.

In the case of Oxford University, for a BA to title him or herself as a MA, you don't
even need to ask the university a new certificate. Read below, in essence, it says
if you have a BA or BFA from Oxford, you can call yourself an MA and there is no
need to take classes or exams as long as you have BA certificate. See below:

'You must have had your BA or BFA conferred in order to take your MA. They can be conferred at the same ceremony provided that sufficient time has elapsed since you matriculated. You should book a degree ceremony through your college. You are not
eligible to take an MA if your undergraduate degree is an Oxford integrated Master’s
degree (MBiochem, MChem, MEng, MMath etc).

The Oxford MA allows you to reach a new status within the University and is not an 
upgrade of your BA or an additional qualification. It therefore has no subject or class. 
The University does not issue degree confirmation letters or ECTS statements as proof 
of your MA. Please use your degree certificate as evidence of this award.'

https://www.ox.ac.uk/students/graduation/ceremonies?wssl=1