The Kiev Expedition of the Polish Duke Boleslaw I the Brave is an episode in the struggle between Sviatopolk I the Accursed and his brother Yaroslav I the Wise for the title of Grand Duke of Kiev.
It occurs when Sviatopolk's father-in-law, Duke Boleslaw of Poland, intervenes on behalf of Sviatopolk, defeats Yaroslav's armies, and temporarily secures the throne for Sviatopolk.The expedition is initially successful for Boleslaw and Sviatopolk, who overrun Kiev and send Yaroslav into exile, but ends with Boleslaw's withdrawal from Kiev and the military defeat of Sviatopolk by Yaroslav, who returns to the Kievan throne from Novgorod.
The return of Yaroslav leads to the golden age of Kiev and the Kievan Rus'.
Chronicles of the expedition include legendary accounts as well as factual history and have been subject to varied interpretations.
