1. English city life in the 19th century. 2. The Battle of the Somme 3. The character of Lady Chatterley 4. Apartheid
I'd expect that whilst they might seem absurdly dated 100 years from now many contemporary British Cambridge applicants today could confidently write essays on (2), a fair few on (3). I'd be really happy if (4) seemed like an odd subject in 100 years' time.
But either way, according to Wikipedia, dueling was a part of British culture though the early 1800s, the last fatal duel was in 1856. Meaning a typical candidate from an elite family in 1899 will have a living relative who has probably at least read public discourse about dueling, and there's a good chance the subject has come up at least once during primary education.
"Swords were drawn and blood was spilled over the election battle of the University Rector."
It was in a semi-public place (the Glasgow University Union building) and may have been reported at the time. Thus, duelling may have been in the news at the time.
"It found no other mention of the event in contemporary university records, newspapers or court summaries."
http://news.scotsman.com/education/Hit-and-myth-Was-Scotland...