His father, Emperor Montoku appointed his forth Prince, Imperial Prince Korehito (later called Emperor Seiwa) as Crown Prince, and tried to let Imperial Prince Koretaka succeed to the throne, however this did not happened as MINAMOTO no Makoto was concerned that FUJIWARA no Yoshifusa would be against this and he remonstrated his concern to the Emperor.
父・文徳天皇は皇太子として第四皇子である惟仁親王（後の清和天皇）を立てた後、惟喬親王にも皇位を継承させようとしたが、藤原良房の反対を危惧した源信の諫言により実現できなかったといわれている。