In 1889, Elisabeth's life was shattered by the death of her only son, thirty-year-old Crown Prince Rudolf. He was found dead together with his young lover Baroness Mary Vetsera. An investigation suggested it was murder-suicide by Rudolf. The scandal was known as the Mayerling Incident, after the name of Rudolf's hunting lodge in Lower Austria, where they were found.
Vetsera met the Crown Prince in November 1888 and began a three-month-long affair with him. Other accounts, however, describe their relationship as being one of three years duration, which would have made Vetsera about fifteen, when they met.
[At Ambassador Reuss's reception in late January 1889] Rudolph noticed me and leaving Stéphanie came straight up to me. "She is there," he said without any preamble; "ah, if somebody would only deliver me from her!" "She" was Mary Vetsera, his mistress of the ardent face. I, too, glanced at the seductress. Two brilliant eyes met mine. One word will describe her. Mary was an imperial sultana, one who feared no other favourite, so sure was she of the power of her full and triumphant beauty, her deep black eyes, her cameo-like profile, her throat of a goddess, and her arresting sensual grace. She had altogether taken possession of Rudolph, and she longed for him to be able to marry her. Their liaison had lasted for three years...At the soirée I was struck by my brother-in-law's state of nervous exhaustion but I thought it well to try and calm him by saying a word or two about Mary which would please him, so I remarked quite simply: "She is very beautiful."...Rudolph left me without replying. An instant later he returned and murmured: "I simply cannot tear myself away from her." - Louise of Coburg
Given her mother's ambitions for her and the fact that Rudolf was married to Princess Stephanie of Belgium, her family and friends found this liaison to be not only foolish, but potentially socially compromising for the family as well. When Hélène discovered that Vetsera had sent Rudolf a personally engraved cigarette case, she raged: "She is compromising herself when she is scarcely seventeen years old and so is ruining not only her life but also that of her brothers and sisters and mother..."
Maureen Allen, an American friend of Vetsera, recalled that she did not take the affair - or any of her earlier ones - frivolously: "[she] was very serious...people gave her credit for not taking love lightly, but rather quite seriously." While Rudolf had not only a wife and child, but other lovers as well, Vetsera did not pursue any other eligible men, but instead focused all her attention on the Crown Prince. She appears to have thought she could be a credible threat to Princess Stephanie, perhaps even to usurping her position and title, but seems to have been ignorant of the fact that Rudolf was simultaneously having a serious affair with the actress Mizzi Kaspar.
Rudolf is reported to have proposed a similar suicide pact to the twenty-four-year-old Kaspar a month prior to his death at Mayerling, which she rejected, presuming it to be a joke. Vetsera may have been Rudolf's second choice in his search for a partner in death, but it appears she did not interpret his proposal as a notion of a desperate man not wanting to die alone. Her family and friends took pains to emphasize that the Emperor and the Vatican would never countenance the dissolution of Rudolf's marriage, and Vetsera no doubt realized that at some point she would have to fulfill her obligation to her family and marry someone who was Rudolf's inferior.
“[I]f I could give him my life I should be glad to do it, for what does life mean for me?”
One of his secretaries is quite emphatic that while Vetsera, whom he saw as a "somewhat superficial and emotional maid" who, while displaying "a vivacity and sparkle that would have done justice to a very bright Frenchwoman", was "a woman without serious thought" and was not the type of woman who usually appealed to the intellectually inclined Rudolf, although he acknowledged that Rudolf was interested in the political opinions of his other lovers to the extent that they were known to be reflections of what their male relatives thought. Rudolf's close friend, Professor Udel, further explained his master's "strange choice": He said that Vetsera shared a certain "mystic temperament" with the Archduke, who could be "the most mystical of men" in that he displayed a "strong vein of superstition".