Final answer:
According to legend, Vladimir the Great chose Eastern Orthodoxy over other religions to legitimize his rule, to align with the power and prestige of the Byzantine Empire, and to foster cultural unity under a common religious identity.
Step-by-step explanation:
The Choice of Eastern Orthodoxy by Vladimir, According to legend, Vladimir the Great chose Eastern Orthodoxy for its spiritual and political benefits. In 987, Prince Vladimir formed an alliance with the Byzantine emperor Basil II, bolstering this union through his conversion from paganism to Christianity and his marriage to the emperor's sister, Anna.
The conversion was also a strategic move for Vladimir to legitimize his rule and align his emerging kingdom with the prestige and power of the Byzantine Empire, which was seen as the continuation of ancient Rome's glory.
Moreover, Vladimir might have been compelled by the religious culture established by missionary efforts like those of St. Cyril, who had previously translated Greek liturgy into Slavonic, promoting a shared religious identity that united much of Eastern Europe.
With the conversion to Eastern Orthodoxy, Kievan Rus' began integrating Byzantine art and architecture, indicating a profound cultural and religious influence. The choice of Eastern Orthodoxy was therefore a blend of spiritual draw and political expediency. It allowed for the centralization of power, cultural unity, and provided a divine endorsement to Vladimir's reign, which was a critical factor in consolidating his authority over Kievan Rus' and its people.