The most controversial member of Japan’s Royal family has died, aged 66, after a two-decade bout with cancer which required several surgeries. The official cause of death has not been revealed.

Prince Tomohito of Mikasa, Emperor Akihito’s eldest cousin, was known for his outspoken personality. The prince fiercely opposed a government recommendation to allow women and their children to ascend to the throne to ease the “succession crisis”, arguing that it would “compromise the imperial family’s significance.” Prince Tomohito also proposed the reintroduction of concubines.

The prince publicly admitted that he had battled alcoholism since he was a teenager, casually discussing many topics often considered taboo in press interviews. Royal family members are prohibited from interfering in political matters.

Prince Tomohito was sixth in line to the throne, and is survived by his parents, his wife and two daughters.