Task: Question Generation
Input (English): 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. The Heian Period is considered a high point in Japanese culture that later generations have always admired. The period is also noted for the rise of the samurai class, which would eventually take power and start the feudal period of Japan.
Output (English): What was the name of the emperor who moved Japan's capital to Heian?