北京最大的四合院，即紫禁城，是一个由大小不一、等级迥异的各种四合院所构成的四合院群。它所体现的正是四合院的本质特征——礼制指导下的人的等级制度。王府是仅次于皇宫的大四合院群。官宦宅邸的规模往往不比王府差，但等级上却不如王府。

The Forbidden City was the largest quadrangle, which was built with different scales and levels of quadrangle complexes. It comprehensively displayed the characteristic of quadrangle-- the hierarchy system guided by ritual. The scales of the mansion for princes were smaller than the largest imperial quadrangle. Although the scale of the quadrangle for the nobility was similar with that of quadrangle of prince, but the former belonged to a lower lever.