《新唐书·列传·卷二十九》
曾祖父名谨，为北周立有功劳，授太师官衔，封燕国公爵号。
曾祖谨，有功于周，为太师、燕国公。
His great-grandfather's name was Jin, who made great contributions to the Northern Zhou Dynasty, was awarded the title of Grand Master, and was named Duke of Yan.