Boris and Gleb
According to the two 11th-century "Lives of Boris and Gleb" (ascribed to Nestor the Chronicler and Jacob the Monk), they were younger children of Vladimir the Great, who favored them over his other children. The "Primary Chronicle" claims that their mother was a Bulgarian woman. Most modern scholars, however, argue that Boris and Gleb had different mothers and were of different ages. Boris, the elder, who was already married and ruled the town of Rostov, was probably regarded as heir apparent to the Kievan throne. Gleb, who was still a minor, ruled the easternmost town of Murom.