The intervention in the Kievan succession crisis by Duke Boleslaus the Brave of Poland in 1015–1019 was an episode in the struggle between Svyatopolk Vladimirovich the Accursed and his brother, Yaroslav the Wise, for the rulership of Kiev and Kievan Rus'. It occurred when Boleslaus, Svyatopolk's father-in-law, intervened on the latter's behalf. The intervention was initially successful as Boleslaus defeated Yaroslav's armies and temporarily secured the throne for Svyatopolk. Svyatopolk, however, was unable to retain his position after Boleslaus withdrew from Kiev and was defeated by Yaroslav in the following year. Chronicles of the expedition include legendary accounts as well as factual history and have been subject to varied interpretations. (Full article...)