ENAfter the restoration of Poland's independence in 1918, part of its political elite turned to the Jagiellonian historical heritage. These ideas had a significant impact on the Eastern policy of Poland during the Polish-Soviet war of 1919-1920 and became the subject of study of both Polish and Soviet historiography. In Polish historiography in an estimation of Jagiellons historical heritage influence on a policy of the country there were two, in many respects opposite, directions which estimations were based first of all on political sympathies and antipathies. In Soviet historiography, the return of some Polish politicians to the Jagiellonian idea was unambiguously interpreted as a desire to justify the expansion of their country to the East. Key words: Polish historiography; Soviet historiography; Jagiellonian heritage; Poland; Soviet Russia; Eastern border of Poland; federalist concept.