 Complete the following phrase:  The Battle of Arcadiopolis was fought in 970 between a Byzantine army under Bardas Skleros and a Rus army, the latter also including allied Bulgarian, Pecheneg, and Hungarian Magyar contingents. In the preceding years, the Rus ruler Sviatoslav had conquered Bulgaria, and was now menacing Byzantium as well. The Rus force had been advancing through Thrace towards Constantinople when it was met by Skleros force. Having fewer men than the Rus, Skleros prepared an ambush and attacked the Rus army with a portion of his force. The Byzantines then feigned retreat, and succeeded in drawing off the Pecheneg contingent into the ambush, routing it. The remainder of the Rus army then suffered heavy casualties from the pursuing Byzantines. The battle was important as it bought time for the Byzantine emperor John I Tzimiskes to settle his internal problems and assemble a large expedition, which eventually 