《旧唐书·列传·卷三十》
封立的各王，即使各自拥有国土，年纪还幼小的，召他们留在京都，用礼法训导他们，用恩惠垂爱他们。
封立诸王，虽各有国土，年尚幼小者，召留京师，训以礼法，垂以恩惠。
Even for enfeoffed kings with their own territories, those who are still young should be summoned back to the imperial palace for instruction with rituals and disciplines and to receive imperial favor and care.