Count Sergei Vasilievich Saltykov (Russian: Сергей Василиевич Салтыков) (c. 1726 – 1765) was a Russian officer (chamberlain) who became the first lover of Empress Catherine the Great after her arrival to Russia.
In her memoirs, Tsaritsa Catherine spread rumours that he was the actual father of her son Paul I of Russia. It was reported that Paul is "almost certainly the child of her lover." Most historians, however, believe that her insinuations were motivated by personal animosity towards Paul and desire to hurt him. Actually, Paul greatly resembled his official father Peter III of Russia in character and appearance. There was very little in common between the pugnacious, stocky Paul and tall, handsome Sergei Saltykov.
Sergei was the son of nobleman Vasili Feodorovich Saltykov (1675 – April 27, 1751). Vasili Feodorovich Saltykov was not a count although a lot of publications have decided to make him one; his wife, whom he married in 1724, was the Princess Maria Alexeievna Galitzina (January 1, 1701 – October 14, 1752), daughter of Prince Alexei Borisovich Galitzine. Prince Galitzine (February 4, 1671 – March 4, 1713) served as a Steward and a Colonel. Galitzine's wife, whom married in January 1684, was Anna Ivanovna Sukina (February 8, 1672 – October 7, 1738). The Saltykovs were an ancient Boyar family, and rivalled the Romanovs in nobility. They descended from a sister of the first Romanov tsar, as well as from several Rurikid branches through female lines. For example, Tsarina Praskovia, the mother of Empress Anna, came from this clan, although her branch was only distantly related to the grandfather of Sergei.
Sergei's wife Matryona Balk was named after her grandmother Modesta Mons, the sister of Anna Mons and Willem Mons. Modesta (better known under her Russian name Matryona) was publicly whipped and exiled to Siberia after Peter the Great had learnt about her husband's affair with his wife Catherine.