Emperor Bidatsu

Emperor Bidatsu (敏達天皇, Bidatsu-tennō; 538 – 14 September 585) was the 30th emperor of Japan, according to the traditional order of succession.

The traditional regnal years of Bidatsu are 572−585, within Asuka period; however, there are no certain dates for this emperor's life or reign. This is the post-Kofun period of the Yamato Kingship.

The names and sequence of the early emperors were not confirmed as "traditional" until the reign of Emperor Kanmu, who was the 50th monarch of the Imperial House.

Source: Wikipedia — https://en.wikipedia.org/wiki/Emperor_Bidatsu