Tonga became a protected state under a Treaty of Friendship with Britain on 18 May 1900, when European settlers and rival Tongan chiefs unsuccessfully tried to oust the man who had succeeded Tāufaʻāhau as king. The treaty posted no higher permanent representative on Tonga than a British Consul (1901–1970). Under the protection of Britain, Tonga maintained its sovereignty, and remained the only Pacific nation to retain its monarchical government. The Tongan monarchy follows an uninterrupted succession of hereditary rulers from one family.