Oleg Svyatoslavich (; 1052 – August 1115) was a Rurikid prince whose equivocal adventures ignited political unrest in Kievan Rus' at the turn of the 11th and 12th centuries. Oleg was a younger son of Sviatoslav Iaroslavich, Prince of Chernigov and his first wife, Killikiya. He might have been either the second or the fourth among the four sons of Sviatoslav Iaroslavich by Killikiya, because their order of seniority is uncertain. According to historian Martin Dimnik, Oleg was born around 1050. Oleg was named after his grand uncle. His baptismal name was Michael. Dimnik writes that "it is highly probable" that Oleg succeeded his brother, Gleb in Tmutarakan after their father appointed the latter Prince of Novgorod in about 1068. Oleg's father and uncle, Vsevolod Iaroslavich made an alliance against their elder brother, Iziaslav Iaroslavich, Grand Prince of Kiev and dethroned him on 22 March 1073. According to Dimnik, Oleg received the Principality of Vladimir from his father who succeeded Iziaslav Iaroslavich in Kiev. In short, Oleg and his cousin, Vladimir Monomachson of Vsevolod Iaroslavichbecame close friends. Monomach writes in his Instruction that Oleg was the godfather of his eldest son, Mstislav. The two cousins together commanded the troops Oleg's father sent to assist Boleslav II of Poland in Bohemia in 1076, according to the Russian Primary Chronicle. Sviatoslav Iaroslavich died in Kiev on 27 December 1077. He was succeeded by his brother, Vsevolod Iaroslavich. The new grand prince seems to have confirmed Oleg's rule in Vladimir, because no source makes mention of a conflict between them. However, the dethroned Iziaslav IaroslavichVsevolod's brother and Oleg's unclereturned with Polish reinforcements. Iziaslav and Vsevolod had a meeting where they reached an agreement: Vsevolod renounced of Kiev, but received Chernigov, the one-time domain of Oleg's father. Iziaslav marched in Kiev on 15 July 1077, while Oleg "was with Vsevolod at Chernigov", according to the Russian Primary Chronicle. The chronicler's remark suggests that Oleg had by that time been forced to leave Vladimir. Failing to get along with his uncle, on 10 April 1077 Oleg fled to his brother Roman who reigned in Tmutarakan. Together with his cousin, Boris Vyacheslavich, who had also settled in Tmutarakan, Oleg made an alliance with the Cumans and invaded Rus' in the summer of 1078. They routed their uncle, Vsevolod on the Sozh River and entered Chernigov on 25 August. The Russian Primary Chronicle accuses Oleg and Boris