On 30 January 1889, the bodies of Archduke Rudolf and his mistress, Baroness Mary Vetsera, were discovered in the royal hunting lodge at Mayerling. The official verdict is that the star-crossed lovers died in a suicide pact after Rudolf’s father, Franz Joseph I of Austria, demanded that he end the relationship. However, there are theories that Rudolf was murdered (Mary’s body was smuggled out of Mayerling in the middle of the night and Rudolf was described as being ‘mentally unbalanced’) …