let's see: henry II was king and possibly ordered Thomas Becket's death, Saladin declared Egyptian independence, Belfast was founded, Venetians took over Verona, Frederick I (Barbarossa) failed to overthrow Pope Alexander III, it was mid-Song dynasty in China, Genghis Khan married Borte then rescued her when she was kidnapped, Muizzudin launched a first attack on India and Eleanor of Aquitaine was put in prison.
As this is an English-language quiz, I don't see where the "MUST" comes from. If you don't know the English name for Ekaterina, the failing is with you, not the quizmaster. If the quizmaster wants to accept alternative answers, the prerogative lies entirely with him.
I always love when there's exactly one question on a quiz that is far more obscure than the rest, judging by the percentage of people who got it right.
The stories surrounding the Transit of Venus are absolutely WILD! One guy (Guillaume Le Gentil) left for India from France a year beforehand, got there like three weeks after it had happened (and obviously conditions for making all of his calculations and observations were dreadful on a boat), decided to stay in India for eight years to wait for next one, missed it due to bad weather, caught dysentery on the boat home, and then got back to France (11 years after setting off) to find that his family had declared him legally dead and taken all of his money and estate while his wife had remarried and he'd been replaced on the Royal Academy of Sciences!