There were formerly (till the early 18th century) two sovereigns; the higher of these, called Tui Tonga (chief of "Tonga), was greatly reverenced but enjoyed little power.
The real ruler and the chief officers of the state were members of the Tupou family, from which also the wife of the Tui Tonga was always chosen, whose descendants through the female line had special honours and privileges, under the title of tamaha, recalling the vasu of Fiji.
Until recent years the forest birds did much to atone for this deficiency, for among them the tui and makomako rank high as songsters, while the apteryxes, kakapo, weka and stitch-bird are of peculiar interest to science.
The seventeen provinces of the colony (at the head of which is either a European or a roko tui or native official) are assessed annually by the legislative council for a fixed tax in kind.
The explanation of the dual kingship is probably this - the Tui Tonga were regarded as the direct descendants of the original head of the family from which the people sprang; regarded with reverence, and possessing unlimited power, they came to misuse this and discontent resulted, whereupon, to protect themselves, they appointed an executive deputy.