Emperor Seimu , also known as Wakatarashi hiko no Sumera mikoto (稚足彦天皇), was the 13th legendary Emperor of Japan, according to the traditional order of succession. Both the Kojiki, and the Nihon Shoki record events that took place during Seimu's alleged lifetime. This legendary Emperor is best known for organizing his local governments by making the first appointments of their kind to provinces under his rule. Seimu had only one recorded wife who bore him a single child; he also had a concubine but she had no children. This is in stark contrast to his father, who is said to have had at least 80 children with multiple wives.

Emperor Chūai , also known as Tarashinakatsuhiko no Sumeramikoto (足仲彦天皇) was the 14th legendary Emperor of Japan, according to the traditional order of succession. Both the Kojiki, and the Nihon Shoki record events that took place during Chūai's alleged lifetime. Chūai is the first monarch to ascend the throne who was not a son of the previous Emperor as the latter's only child died young. He is also noted for having his capital in Kyushu, rather than Yamato like his predecessors. The records state that Chūai had a wife named Okinagatarashihime-no-Mikoto, and 2 consorts that all bore him 4 children.