Emperor Ōjin
The tomoe emblem established itself as a common emblem during the Fujiwara ascendency of the late Heian period, around the 10th-11th centuries, and proliferated through to Kamakura times. It is thought that a resemblance between the tomoe and the Emperor Ōjin found in the Nihongi may also account for its rising popularity among samurai, since Ōjin was apotheosized as a god in Hachiman shrines.