In 1858 Te Wherowhero was installed as the first Māori King (taking the name Pōtatau), his purpose being to promote unity among the Māori people in the face of Pākehā encroachment. When Pōtatau died in 1860, Tāwhiao, his sister Te Paea Tiaho, and Wiremu Tamihana Tarapipipi of Ngāti Hauā were candidates to succeed him. Tāwhiao was chosen and reigned for thirty-four years during one of the most difficult and discouraging periods of Māori history. During this period there were two governments "de jure"; English law and governance prevailed within the British settlements and Māori custom over the rest of the country, although the influence of the King was largely confined to the Waikato and even there chiefs such as Rewi Maniapoto only cooperated with the king when it suited them. However the Pākehā population was increasing rapidly while the Māori population was unknown as there was no reliable census of Maori and Pākehā / Maori for 80 years. Because Maori separated themselves from Pākehā, many believed, wrongly, that the Maori population was declining rapidly. This was also the period when British industrial, trade and political power was at its height. The presence of an independent native state in the central North Island was officially ignored by the government until it developed the potential to undermine the colonial government's sovereignty.