The thesis concentrates on the life and work of Nikolai Lvovich Okunev (1885- 1949), an important historian of art and representative of Medieval studies, Professor at Charles University in Prague. His research work, that already began during his studies at the University in Saint Petersburg, meant an important contribution to studies in the field of Old Russian, Byzantine and Medieval Armenian Art and Architecture. After he had left his native country for political reasons, he was living in the Kingdom of Serbs, Croats and Slovenes in 1920-1923, then in 1923-1949 in Czechoslovakia. For more than 20 years he lectured at Charles University in Prague where he educated a number of disciples. He was a member of the Institute of Slavonic Studies...