Maria Dolgorukaya (died 1573/1580 ?) was a legendary wife of Ivan IV ("the Terrible") of Russia, possibly his 5th or 7th. The marriage (unauthorized by the Church) could be celebrated in 1573 or 1580. As the dark legend says, she did not bear the tsar any children and either was revealed to have a lover or after the 1st night, the tsar discovered she wasn't a virgin. Ivan had her drowned.
There is no evidence of her existence in medieval sources. The first mention can be found in 19th-century Russian literature. Nikolay Kostomarov in 1866 wrote that the notice about her was found by Afanasiy Byichkov in some manuscript in Imperial Public Library.
Of all the 8 wives of Ivan the Terrible, only Maria Dolgorukaya and Vasilisa Melentyeva (who is also considered as 19th-century fake) don't have graves or any mentions in official court documents.