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In page Family of Vladimir the Great:

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Several authorities, notably Rydzevskaya ("Ancient Rus and Scandinavia in 9-14 cent.", 1978), hold that later skalds confused Vladimir's wife Olava with his grandmother and tutor Olga, with Allogia being the distorted form of Olga's name. Others postulate Olava was a real person and the mother of Vysheslav, the first of Vladimir's sons to reign in Novgorod, as behooves the eldest son and heir. On the other hand, there is no evidence that the tradition of sending the eldest son of Kievan monarch to Novgorod existed at such an early date.[citation needed]