Let me emphasize from the start that to be a real gentleman, it must be to Cambridge, rather than Oxford, that you owe your allegiance. Everybody knows that Oxford and Cambridge are England's oldest universities, and of the two, Oxford is the one regarded by Americans as the most elite. People refer to an Oxford accent, but rarely refer to a Cambridge one. This presumed superiority of Oxford over Cambridge is probably because Cambridge University was founded by students from Oxford, a couple of years after students from the University of Paris settled at Oxford. Do not be misled.
As Bertrand Russell pointed out, after he was temporarily exiled to Oxford from Cambridge, Oxford did not have a science department until the twentieth century. Even then, while Russell was teaching philosophy at Oxford, the science lectures consisted only of a man showing magic lantern slides of famous scientists, and giving outlines of their achievements. Stephen Hawking did graduate from Oxford, but even he had to do his postgraduate studies at Cambridge. He is now Lucasian Professor of Mathematics at Cambridge, a post once held by Isaac Newton. Any true university must have a faculty in which original research can be done in the complete range of sciences. Oxford, therefore, was not a real university until after the Second World War.
Cambridge's claims to scientific fame do not rest solely on Newton and Hawking. Just one Cambridge college, Trinity, has produced more Nobel Prize winners than the whole of France.
Even in the study of Classics, Oxford was inferior. Unlike Cambridge, Oxford did not until fairly recently use the Continental pronunciation of Latin, which linguists, by the study of poetry, had discovered to be more accurate.
Scholars from that most elite of English public schools, Eton, traditionally go up to Cambridge. At one time, King's College only took its students from Eton. St. John's College, Oxford, on the other hand, traditionally took its students from the Merchant Taylor's School. Then there is that most elegant of student pastimes, punting. The most desirable Cambridge colleges are on the Backs, that part of the River Cam onto which the backs of those colleges open. This is a most beautiful environment for punting, along with the Upper Cam, or Granta, and the village of Grantchester. Oxford has only one college on a river, Magdalen (pronounced Maudlin).
Other articles on this site will help you to establish your status as a Cambridge man. You do not need to lie. Fortunately, no true Cambridge man, and especially no gentleman adventurer, would boast about his alma mater. You only have to casually mention aspects of Cambridge life, and have the bearing of a Cambridge man, and allow others to reach their conclusions. If you are faced with the specific question of whether you are a Cambridge man, you are, as a gentleman adventurer, entitled to be mysterious. Alternatively, you may hint that you were rusticated (expelled for one term for some roguish act or prank) and decided not to return. To claim that you were 'sent down' (permanently expelled) would require a sin so spectacular that your supposed contemporaries at Cambridge would expect to remember it, so it's best to stick with rustication.
Part of the bearing of a Cambridge man is to give the impression of knowing something about
everything. To achieve this end, Cambridge men are quite prepared to bluff. Therefore, by
giving the impression that you are a Cambridge man, you are being the ultimate Cambridge man.