Sione Tupou Mateialona/en

Following the establishment of the British protectorate over Tonga, Mateialona became prime minister. Fortunately, he worked well with the British consul, Hamilton Hunter.

In 1909, the Maʻa Tonga Kautaha cooperative trading society was founded to sell copra. This was a great success, providing the Tongan participants with much greater profits than they had previously achieved through dealings with foreign traders. Unsurprisingly, the foreign traders disapproved and initiated legal proceedings, turning the Kautaha into a political issue. King Tupou was pressured to support the Tongans. However, the British sided with the foreigners. As Mateialona was still friends with the British, he fell from favour. He resigned in May 1912, supposedly to retire, although he may have remained on as caretaker until September of that year. Tēvita Polutele Kaho, the chief of police, succeeded him.

In 1918, he became Governor of Haʻapai, one of the first appointments made by the new Queen, Sālote Tupou III.

Although Mateialona was a grandson of Tupou I, he did not hold an official chiefly rank. This was because his father, Isileli Tupou, had been declared illegitimate by Tupou I and his mother came from a less prominent family. Nevertheless, as the House of Tupou lacked heirs at the time, he was still a possible candidate for succession to the throne. In 1921, Sālote rewarded his support by elevating him to the nobility and granting him the title of Tupoutoʻa, essentially making him crown prince.
I.C. Campbell; Island kingdom; Canterbury press, 2001