Father-in-law of the composer (b. 24 February/8 March 1811; d. 2/14 April 1871), born Ivan Andreyevich Milyukov (Иван Андреевич Милюков).
Ivan was the son of Andrey Milyukov (1777–1831) and his wife Aksinya Ivanovna (b. Golosova). On 25 January/6 February 1839 he married Olga Yaminskaya (1821–1881), and they had ten children: Aleksandr (1840–1885); Yelizaveta (1842–1912); Nikolay (1844–1846); Mikhail (1845–1869); Antonina (1848–1917), wife of the composer; Olga (b. 1851); Mariya (b. 1854); Aglaida, also known as Adel (b. 1855); Ivan (b. 1857); and Anna (b. 1859).
Tchaikovsky never met his father-in-law, who died six years before his engagement to Antonina.