Tatiana Day (Russian: Татьянин день, Tatyanin den' ) is a Russian religious holiday observed on January 25 according to the Gregorian calendar, January 12 according to the Julian. It is named after Saint Tatiana, a Christian martyr in 3rd century Rome during the reign of Emperor Alexander Severus.
In 1755 on the name day of Ivan Shuvalov's mother Tatiana Rodionovna, his mistress Empress Elizabeth of Russia endorsed his petition to establish a university in Moscow. The church of Saint Tatiana was later built in the university campus, the Russian Orthodox Church declared Saint Tatiana the patron saint of students, and Tatiana Day has become celebrated as Russian Students Day.