Some 20 to 25 years after the rediscovery of New Zealand by Captain Cook in 1769, unorganised settlement of the country gradually began. The first European settlers to come to New Zealand were mainly whale and seal fishermen, shipwrecked sailors, and escaped convicts from Australia. These were followed by traders, principally in timber and flax, and missionaries. It has been estimated that the population of Europeans in 1800 was about 50 persons, rising to some 200 by 1815, and at least to 1,000 by 1839. Settlement at first was slow because of the hostility of the Maoris, the opposition of the influential Church Missionary Society, and the reluctance of the British Government to establish sovereignty over New Zealand.