Sviatopolk's mother was a Greek nun captured by Sviatoslav I in Bulgaria and married to his lawful heir Yaropolk I, who became Prince of Rus in 972. In 980, Yaropolk's brother Vladimir had him murdered, and the new sovereign married his predecessor's wife, who gave birth to a child. Thus, Sviatopolk may have been the eldest of Vladimir's sons, although his parentage has been questioned. When Sviatopolk was eight years old, Vladimir put him in charge of Turov and later arranged his marriage with the daughter of the Polish duke Bolesław I Chrobry of Poland. The young princess came to Turov together with Reinbern, the Bishop of Kolberg. Dissatisfied with Vladimir and encouraged by his own wife and Reinbern, Sviatopolk began preparations for war against Vladimir, probably counting on support from his father-in-law. Vladimir soon discovered Sviatopolk's intentions, however, and threw him, his wife and Reinbern in prison. Reinbern died in prison.
Biography according to domestic sources
Not long before Vladimir's death, Sviatopolk was freed from prison and sent to govern the town of Vyshgorod several miles from Kiev. In 1015, Sviatopolk's retinue concealed Vladimir's death from him to prevent him from claiming the Kievan throne. When Sviatopolk learned of Vladimir's demise, he seized power in Kiev almost immediately. The citizens of Kiev did not show much sympathy for Sviatopolk and, therefore, he decided to distribute presents in order to win them over. Then, he decided to rid himself of three of Vladimir's sons, Boris, Gleb, and Sviatoslav, whose claims for the Kievan throne threatened his power. Boris presented most danger to him because he had been in charge of Vladimir's druzhina and army, and enjoyed the support of the citizens. He sent the boyars of Vyshgorod to execute Boris. Boris and his manservant were stabbed to death when sleeping in a tent. The prince was discovered still breathing when his body was being transported in a bag to Kiev, but the Varangians put him out of his misery with the thrust of a lance. Sviatopolk's cold-blooded reprisal earned him the nickname of the Accursed. The news of this triple murder reached another son of Vladimir, Yaroslav, Prince of Novgorod, who decided to go to war against Sviatopolk with the support from the citizens of Novgorod and the Varangians. The battle took place in 1016 not far from Lubech, near Dnieper river. Sviatopolk was defeated and fled to Poland. In 1018, he returned to Rus', defeated Yaroslav with the help from his father-in-law and seized Kiev. Bolesław I Chrobry of Poland and his army remained in Rus' for several months, but later left for Poland. On his way to Poland, Bolesław seized some of the Cherven towns. Meanwhile, the posadnikKonstantin Dobrynich and other citizens of Novgorod persuaded Yaroslav to go to war against Kiev once again. Sviatopolk was defeated and fled to the steppes. Soon he returned with the Pecheneg army and attacked Yaroslav on the Alta River, but was once again defeated and fled to Poland, eventually dying on his way there. Sviatopolk's death could have been procured by a descendant of Valuk Conqueror who in 1018 helped him and his father-in-law Bolesław I in expedition against Yaroslav.
Biography according to foreign sources
During the last century, the traditional account of Svyatopolk's career has been somewhat modified. It has been argued that it was Boris who succeeded Vladimir in Kiev, while Svyatopolk was still in prison. One Norse saga called Eymund's saga, with remarkable details, puts on Yaroslav the blame of his brother Burizlaf's murder. This Burizlaf, however, may be Svyatopolk as well as Boris. Therefore, it has been suggested that Svyatopolk ascended the throne after Boris's assassination and tried to fend off Yaroslav's attacks as well as to punish his agents guilty of Boris's murder. The chronicle of Thietmar of Merseburg, who died in 1018, could have been regarded as the only contemporary and unbiased account of events, if it were not for the fact that Thietmar's data could have been supplied by Svyatopolk himself during his brief exile at the Polish court. Unfortunately it can be interpreted ambiguously as far as the question of Svyatopolk's guilt is concerned. One place in his chronicle can be understood as telling that Svyatopolk escaped from Kiev to Poland immediately after his father's death. But Thietmar states that Boleslaus I of Poland firstly supported his son-in-law against Yaroslav in 1017, which is the date, according to the Russian Primary Chronicle, of Svyatopolk's first defeat by Yaroslav. Preparing a campaign against Kiev, Boleslaus abruptly stopped a successful war against the German Emperor Henry II. So, it is unlikely that Svyatopolk had been present at his court since 1015, which is often supposed by the historians that consider Yaroslav guilty of Boris and Gleb's murders.
