Simplify the following text for a Grade 12 native English-speaking person.
Original: Sujin is a posthumous name . It is undisputed that this identification is Chinese in form and Buddhist in implication , which suggests that the name must have been regularized centuries after the lifetime ascribed to Sujin , possibly during the time in which legends about the origins of the Yamato dynasty were compiled as the chronicles known today as the Kojiki .
Simplified: This emperor 's posthumous name must must have been regularized many centuries after the lifetime ascribed to Sujin .