Namesakes
Bulgarian Kings and Tsars:
2 tsars
Tsar Konstantin I 1257-1277 
Tsar Konstantin II 1397-1422
Bulgarian Presidents and Prime Ministers:
2 prime ministers
(prime minister) Konstantin Stoilov 1887; 1894-1899
(prime minister) Konstantin Muraviev 1944
Estonian Presidents and Prime Ministers:
1 state elder/prime minister/president
(state elder/prime minister/president) Konstantin Päts 1921-1922; 1923-1924; 1931-1932; 1932-1933; 1933-1934; 1934-1937; 1938-1940
Nobel Prize Winners:
1 physics
(physics) Konstantin Novoselov 2010
Notable Actors and Entertainers:
3 actors
Konstantin Stanislavski 1863-1938
Konstantin Lavronenko 1961-
Costa Ronin 1979-
Notable Athletes:
1 tennis
(tennis) Konstantin Kravchuk 1985-
Notable Filmmakers:
1 director
Konstantin Stanislavski 1863-1938
Notable Military Figures:
1 officer
Konstantin Rokossovsky 1896-1968
Notable Scientists and Inventors:
1 engineer, 1 physicist
Konstantin Tsiolkovsky 1857-1935
Konstantin Novoselov 1974-
Olympic Medalists:
2 silver, 1 bronze, 1 silver/bronze/gold
(silver/bronze/gold) Elmer Niklander (middle name Konstantin) 1912; 1920 discus throw - both hands; shot put - both hands; discus throw; shot put
(silver) Konstantin Volkov 1980 pole vault
(bronze) Konstantin Dubrovin 1996 swimming - 4x200 m freestyle relay
(silver) Konstantin Ushkov 1996 swimming - 4x100 m freestyle relay
Other Leaders:
1 general secretary
General Secretary Konstantin Chernenko 1984-1985 Soviet Union
Russian Grand Dukes and Tsars:
1 duke
Duke Konstantin 1216-1218