Árpád Plesch (25 March 1889 – 16 December 1975) was a Hungarian financier, banker, and lawyer.
[4] He owned a celebrated collection of rare botanical books and esoteric pornography.
Plesch firstly married Léonie Caro Ulam (1883–1951), secondly to her daughter Marysia Ulam Krauss Harcourt–Smith (1912–1976), through which he was affiliated with being the step-grandfather of French financier Arpad Busson, which was named after him.
[5] In his memoir, Adventures of a mathematician, Ulam wrote: My uncle Michael's wife happened to live in Paris at the time and she kindly offered to receive me and to send to my modest hotel her chauffered limousine to take me sightseeing.
I was so embarrassed at the thought of being seen arriving in a Rolls-Royce or a Duesenberg at the Louvre or some other museum, it felt so incongruous, that I declined her offer.In 1954, Plesch married Etti Countess von Wurmbrand–Stuppach, colloquially known as Etti (1914–2003), an Austrian socialite, daughter of Count Ferdinand von Wurmbrand–Stuppach (1879–1933) and his wife May Baltazzi (1885–1981), a cousin of Baroness Mary Vetsera and mistress of Crown Prince Rudolf of Austria.