The order of succession to the throne of
Tonga is laid down in the 1875 constitution. The crown descends according to
male-preference cognatic primogeniture. Only legitimate descendants through legitimate line of King
George Tupou I's son and grandson, Crown Prince
Tēvita ʻUnga and Prince
ʻUelingatoni Ngū, are entitled to succeed. A person loses their right of succession and deprives their descendants of their right of succession if he or she marries without the monarch's permission.