However, Imperial Princess Isoko supposedly did not get permission from her father Emperor and therefore it is said that the first case of koka with an emperor's approval is that of Imperial Princess Teishi, a daughter of Emperor Sanjo.
ただしこの時は父天皇の許可を得ていなかったと見られ、天皇により内親王の降嫁が裁可されたのは、三条天皇皇女禔子内親王の例が最初とされる。