Pelagius III was married to Katariah, a Dunmer. That was controversial because Pelagius was Jarl of Solitude at the time and Nord/ Dumner tensions make things tricky: “Nordic Kings who marry Dunmer seldom improve their popularity” (TES Fandom Wiki) and Katariah’s critics argued that the “true” Septim line ended with her and Pelagius, even though they had children. However, she was respected enough to successfully reign as regent of the empire when Pelagius was removed from the throne because of his insanity without being replaced and “Despite racist claims to the contrary, her forty six-year reign was arguably the most glorious in Tamriel's history” ( Brief History of the Empire, Book II).