From the Turkic name
Bogoris, perhaps meaning "short" or "wolf" or "snow leopard". It was borne by the 9th-century king Boris I of Bulgaria who converted his country to Christianity, as well as two later Bulgarian emperors. The name was popularized in the Slavic world due to the 11th-century Saint Boris, who was a Russian prince martyred with his brother Gleb. His mother may have been Bulgarian. Another famous bearer was the 16th-century Russian emperor Boris Godunov, later the subject of a play of that name by Aleksandr Pushkin.