西周之世因施行宗法制度而盛極一時，但王室東遷後逐漸衰微，無法維繫原有的禮樂文明，以致諸侯力征，戎狄入侵，天下大亂；究其根源，當與以嫡長子繼承爲中心的宗法制度無法順利執行有重大關係。王朝之根本繫諸於天王，欲釐清春秋時期天下大亂之原因，周王室由盛入衰實爲重要關鍵，而欲解析周王室盛衰變化之軌跡，其世系傳承中之非常態現象更是癥結所在。本論文解析王室中四次嫡庶爭位事件，發現亂端皆肇因於幼庶受寵所形成的「匹嫡」現象，是以引爆一次比一次嚴重的爭位之亂，以致嫡長子繼承制無法順利執行，也嚴重斷害宗法之制中的「親親尊尊」精神，王室遂日趨衰微。因此，匹嫡現象是東周王室寖衰之根源所在。 When Zhou royal (周王室) moved capital to east city, national power of East Zhou was less than West Zhou's. The power of vassals was getting mighty. The government cannot control the social peace. The reason came from the succession to the throne system collapsed. The king denoted on the others son likely the eldest son. This phenomenon impacted the succession system. The eldest son couldn't succeed the throne smoothly. The power of East Zhou royal was getting declining. This paper presents the king denoted on the others son likely the eldest son was the key point of power declining.
