of the main motivating forces, if not the actual architect, of many of the policies adopted" by the three brothers. The "triumviri" closely cooperated in the following years. In 1059 they liberated their uncle Sudislav, whom their father had sent to prison around 1035. They made a joint expedition "by horse and ship against the Torks" or Oghuz Turks, according to the Russian Primary Chronicle, in 1060. On hearing of the arrival of the Rus' forces, the Torks fled from their lands without resistance. In 1065, Sviatoslav led his troops against his nephew, Rostislav Vladimirovich, who had in the previous year forcibly expelled Sviatoslav's son, Gleb, from Tmutorakan. Upon Sviatoslav's arrival, Rostislav withdrew from this important center of his uncle's domains, but he reoccupied it after Sviatoslav had returned to Chernigov. A distant cousin of the "triumviri", Vseslav Briacheslavich (Prince of Polotsk), attacked Pskov in 1065, according to The Chronicle of Pskov. Vseslav Briacheslavich could not take this town, but he seized and plundered Novgorodwhich had been ruled by Iziaslav of Kiev's son, Mstislavin the next winter. Izyaslav, Sviatoslav and Vsevolod soon united their forces and set forth against Vseslav, "though it was the dead of winter", according to the Russian Primary Chronicle. They routed Vseslav's army by the Nemiga River (near Minsk) on 3 March 1066. Vseslav, who fled from the battlefield, agreed to enter into negotiations with the "triumviri", but they treacherously captured him at a meeting at Orsha in early June. The Cumans, who had emerged as the dominant power of the Pontic steppes in the early 1060s, invaded the southern regions of Kievan Rus' in 1068. The three brothers together marched against the invaders, but the Cumans routed them on the Alta River. From the battlefield, Sviatoslav withdrew to Chernigov and regrouped his troops. He returned to defeat the Cumans with a smaller force at the town of Snovsk on 1 November, thus enhancing his prestige among the populace. In the meantime, the townspeople of Kiev had dethroned and expelled Sviatoslav's brother, Iziaslav. Taking advantage of Iziaslav's absence, Sviatoslav sent his own son, Gleb, to Novgorod to rule the town. Iziaslav returned at the head of Polish reinforcements. The townspeople of Kiev sent messages to Sviatoslav and Vsevolod, imploring them to come to their "father's city" and defend it, according to the Russian Primary Chronicle. Sviatoslav and Vsevolod requested Iziaslav "not to lead the Poles in