Original: The conventionally accepted names and dates of the early emperors were not to be confirmed as '' traditional '' until the reign of Emperor Kammu ( 737 â '' 806 ) , the 50th sovereign of the Yamato dynasty .
Simplified: The conventionally accepted names and sequence of the early emperors were not to be confirmed as '' traditional '' until the reign of Emperor Kammu , who was the 50th monarch of the Yamato dynasty .