Important questions related to Māori conversion have been raised. What did conversion mean to Māori and why were they converted? These lead to subsidiary questions: what of their traditional beliefs did they set aside, and what did they retain? How did the Christian God sit alongside those of Māori? Spirituality invested the very landscape they inhabited, and fauna and flora were (they believed) derived from deities with whom they were inextricably linked. These things are not easily dismissed. Maori adhered to concepts of mana, tapu and mauri and maintained rahui and kaitiakitanga. Māori believed in the sanctity of “this world” whereas for the promoters of Christianity “this world” was tarnished by sin, redemption being found in the after-life and the “next world”. Small wonder, then, that out of this spiritual melting-pot there emerged charismatic Māori leaders or prophets with their own adaptations or modifications of Christianity.
Critics of the missionary project, and there were many, were quick to point out the time taken to obtain conversions to Christianity. Trying to change the entrenched spiritual beliefs of a population that had spent hundreds of years isolated from other cultures –and thousands more from those that gave rise to the major religions – would under any circumstances pose major challenges. The first baptism took place ten years after Marsden first arrived in the country. While the preceding years had not been idle, that conversions arrived in any number was in significant measure owed to the Williams brothers.
They were not alone in this enterprise as other denominations were actively seeking converts, notably the Wesleyan and Roman Catholic missions. The former tended to work on the west coast of the North Island and to a limited extent in the South Island. As a non-conformist body they were more in tune with the practices and approach of the Church Missionary Society. The Catholics came later and found many districts occupied by missionaries of other faiths. They were regarded with suspicion by the Government and the protestant missionaries, on doctrinal grounds as well as their potential to encourage French colonization.
It was the cultural package as a priority, rather than as an accessory, that was blamed for the slow start to conversions. Marsden was a staunch advocate of “civilizing before proselytizing” believing that Māori would embrace Christianity once the practical benefits of a “superior” European culture had been absorbed. Henry and William Williams wanted to reverse this proposition and this, it has been argued, ultimately led to an increased number of conversions. The missionaries who preceded them held similar views that were passed on to Marsden and the Church Missionary Society without much notice being taken. But a continuing lack of conversions and the combined authority of the Williams brothers allowed a change of policy and emphasis.
Their position was not a total reversal of Marsden’s ideas. They kept intact those parts that could be expected to further the mission’s objectives such as setting up schools, advancing literacy, printing books, treating the sick, and promoting agriculture. These, along with renewed emphasis on missionary fluency in Māori, were the proximal means of promoting Christianity. It could also be argued that by the time conversions and baptisms started to pick up, Māori were well acquainted with the elements of European culture they found useful, and to an extent this approach to the programme had already done its work.
The first Māori baptism, by Kendall of Maria Ringa, occurred in 1823, prior to the arrival of Henry Williams. It appeared to be one of convenience rather than conviction.  This was followed in 1824 by Henry Williams’ baptism of Rangi, a Māori chief dying of tuberculosis. Although this might seem to signal an improvement on the barren years of his predecessors, it was not until the end of the 1820s that the numbers started to rise. Māori children, in a live-in arrangement with missionary families and part of their schools, seemed to have been the most productive source of converts.
By the 1830s a steady number of baptisms and conversions were taking place, greatly improved through the efforts of William Williams on the East Coast, assisted by Māori teachers and fellow missionaries. In 1841 William Williams recorded 8,600 attending services conducted largely by Māori pastors. Reasons for this success are complex, but William Williams thought war weariness, disease, and advancing literacy, were among them. It has been noted that a striking feature of the conversion on the East Coast was its speed, facilitated by these factors and the growth of the Māori pastorate.
As the century wore on missionary influence waned, owing to formal colonization, the growth of a mainstream church, and Māori devising their own modifications of Christianity. Among Māori themselves the novelty of Christianity was dying away, and by the late 1850s the Church Missionary Society was unwilling to provide further support for its missionaries in New Zealand. As far as his health would let him, Henry Williams remained active in the Bay of Islands until his death in 1867. In 1859 William Williams was consecrated Bishop of Waiapu and he continued to support the Māori pastorate in his diocese, although after the Hauhau rebellion much of his attention was diverted from the location that had been the focus of his earlier labours. Missionary achievements, it would seem, were most productive in the 1830s and 40s, with the decades following seeing socio-economic, and cultural change that would impact the conduct of Christianity among Māori and Europeans, as colonisation fastened its grip.
Sowing the seeds of Christianity allowed the development of other religious movements among Māori, mediated through Māori prophets, with elements of the Christian faith in their structure. The first of these was the cult figure of Papahurihia, a tohunga and visionary from the Taiamai area, who emerged in the early 1830s and obtained a number of followers, some of whom engaged in discussions with Henry Williams about their beliefs. The movement was short-lived. Later, and more notable were the Pai Marire or Hauhau, and Ringatū movements. The former was associated with violent conflict and was one of the reasons for William Williams and his family leaving the mission station at Te Waerenga-a-hika and ultimately moving to Napier in 1865. It has been said that the Hauhau and Ringatū movements – two of a number of political and religious affiliations affecting East Coast Māori– were provoked by the actions of the Government and settlers. These movements retained small numbers of adherents well into the 20thcentury, added to by the more prominent Ratana Church in the 1920s. Although now found among other Christian churches, five Māori Hui Amorangi (Dioceses) within the Tikanga Māori are to be found in the Anglican Church in New Zealand.
 p. 46, Porter, F. (ed.) 1974, Loc. cit.
 “this world” concerns came to be the province of environmental movements, widely and increasingly shared in the 20th and 21stcenturies, concerns that continue to be shared by Maori.
 p. 145, Fisher R., 1975. Henry Williams’ Leadership of the CMS Mission to New Zealand. New Zealand Journal of History, v. 9(2): pp.142-153.
 p. 43, Porter, F. 1974, loc.cit.
 It was not recognized in CMS reports, as it did not have proper sanction from the mission in view of doubts about her religious conviction. Maria Ringa was to marry the Pakeha Phillip Tapsell –the reason for carrying out the baptism. The marriage lasted a day. P. 79, Salesa, I.P. 2011. Racial Crossings: Race, Intermarriage, and the Victorian British Empire. Oxford University Press, Oxford, 295pp.
 Marianne Williams, 24.12.1828, pp. 168,169, in Fitzgerald, C. (Ed.) loc. cit.
 p. 46, F.W.Williams, n.d., Through Ninety Years, 1826-1916 Life and Work among the Maoris in New Zealand. Whitcombe and Tombs, Auckland, 360 pp.
 p. 46, Porter, F, 1974, loc.cit.
 pp. 28-35, Oliver, W H and Thomson, J M, 1971. Challenge and Response. The East Coast Development Research Association, Gisborne., 251 pp.
 pp. 582-583. Porter, F., 1974, loc. cit. Although the situation was considerably more complex than this summary suggests
 p. 87, Oliver, W H and Thomson, J M, 1971, loc.cit.
Published in 1867, William Williams' Christianity Among the New Zealanders was written to counter adverse criticism in England, in the press, of missionary endeavours in New Zealand. The book drew on publications of the Church Missionary Society, as well as his personal observations and those of other missionaries. It includes data on baptisms and church attendances.