Query: The Heian period began in what year?
Context: The Heian period was preceded by the Nara period and began in 794 A.D after the movement of the capital of Japan to Heian-kyō (present day Kyōto京都), by the 50th emperor, Emperor Kanmu. Kanmu first tried to move the capital to Nagaoka-kyō, but a series of disasters befell the city, prompting the emperor to relocate the capital a second time, to Heian.