《新唐书·列传·卷一百四十五》
王族是第一骨，妻子也是同族人，生的子女也是第一骨，不娶第二骨的女子为妻，即使娶了，只能做妾。
王族为第一骨，妻亦其族，生子皆为第一骨，不娶第二骨女，虽娶，常为妾媵。
The royal family was the first bone, and the wife was also a compatriot, and the children born were also the first bone. They did not marry the daughters of the second bone as wives, and even if they did, they could only be concubines.