Among the pioneers of the Slavic studies (including the Bulgarian studies) were the Czech and Slovak personalities such as Josef Dobrovský, František Ladislav Čelakovský, Jan Kollár, Karel Jaromír Erben and foremost Pavel Josef Šafařík, who had close ties with Bulgarian students in Prague.
This was followed by the so-called Czech invasion into Bulgaria, of which Šafářík's grandson Konstantin Josef Jireček was the main personality.
Countless other Czechs took part in build-up of modern education and judiciary, cultural institutions as well as railways in Bulgaria.
Large numbers of Bulgarians escaped to Czechoslovakia after Bulgaria (at the time ally of Nazi Germany) was occupied by the Red Army at the end of the second world war.
Thousands more benefited from joint program of governments of Czechoslovakia and Bulgaria in years 1946–8, in which whole families immigrated to the areas from which the Germans were expelled.