The long reign of King
George Tupou I (), the first constitutional monarch of Tonga, saw six different heirs apparent to the Tongan throne. The only
legitimate son of the King,
Vuna Takitakimālohi, died unmarried in January 1862, leaving the King without an heir. The succession would remain vacant for thirteen years until the promulgation of the
Constitution of Tonga in 1875, which legitimized Vuna's half-brother
Tēvita ʻUnga and named him Crown Prince. By 1889, the King would outlive ʻUnga and all three of his grandchildren –
ʻUelingatoni Ngū,
Nalesoni Laifone and
ʻElisiva Fusipala Taukiʻonetuku. That left his great-grandson Tāufaʻāhau, Fusipala's son, as the next Crown Prince, who would succeed his great-grandfather in 1893 as
George Tupou II. ==Crown Princes of Tonga since 1845==