he was the author of more than 150 works on the history of kievan rus', muscovy, 19th-century russia, lithuania and belarus, on the social-political movement, peasants' question and the ethnography of belarus. notably, the majority of his works were of a scientific-analytical nature. he extensively sourced his works on the materials from more than 20 archives in moscow, saint petersburg, kiev, vilna, warsaw, cracow, lviv, kostroma, yaroslavl', novgorod, nyasvizh etc. many of his works remain unpublished. he was awarded the order of saint vladimir 4th grade (april 1916) for his scientific work.