Leaders called Boris

How many countries have been ruled by a Boris?
— Russia has had two Borises in charge. Boris Godunov was tsar between 1598 and 1605, during the Time of Troubles, and was credited with improving education in the country, importing foreign teachers and sending Russian children abroad for schooling. Boris Yeltsin was president of Russia from July 1991 to December 1999, becoming the first post-communist leader of the country.