Wife of the pianist Aleksandr Ziloti and daughter of the Russian businessman and art collector Pavel Tretyakov, born Vera Pavlovna Tretyakova (Вера Павловна Третякова) (b. 1866; d. 1940), and known after her marriage in 1886 as Vera Pavlovna Ziloti (Вера Павловна Зилоти). She was also a cousin of Tchaikovsky's sister-in-law Praskovya.
Correspondence with Tchaikovsky
One letter from Tchaikovsky to Vera Ziloti has survived, dating from 1892, and is available in an English translation on this site: