The tradition of celebrating Tatiana's Day on January 25th is linked to the founding of Moscow State University. Russians believe the patron saint, Tatiana, was named after the mother of Count Ivan Shuvalov.
On January 25, 1755, Count Ivan and Empress Elizabeth the Great officially established the first Russian university in Moscow. Coincidentally, Tatiana's name day also falls on January 25th. This confluence of events led to the university's establishment and Tatiana's name day becoming synonymous with the celebration of Russian students.
This tradition has been observed in Russia for over 200 years.