During his voyage, Cook also visited New Zealand, first discovered by Dutch explorer Abel Tasman in 1642, and claimed the North and South islands for the British crown in 1769 and 1770 respectively. Initially, interaction between the indigenous Māori population and Europeans was limited to the trading of goods. European settlement increased through the early decades of the 19th century, with numerous trading stations established, especially in the North. In 1839, the New Zealand Company announced plans to buy large tracts of land and establish colonies in New Zealand. On 6 February 1840, Captain William Hobson and around 40 Maori chiefs signed the Treaty of Waitangi. This treaty is considered by many to be New Zealand's founding document, but differing interpretations of the Maori and English versions of the text have meant that it continues to be a source of dispute.