This study is a fruit of joined intercultural research. The authors, an Asian and a European, look at the encounter between Christianity and the realm of the indigenous people of Nias and the Batu Islands (the Ono Niha) and their culture. During the course of one century (1865-1965), two missionary societies, the Rhenish Mission and the Dutch Lutheran Mission, were each propagating a certain type of Protestantism among the Ono Niha. The course of Christianization transformed the Niasan culture. In its turn, the Niasan culture shaped a unique type of Christianity. The two entities involved, however, were not equal. The stronger Christianity grew, the more uncompromising it became towards the indigenous culture, particularly primal religion. Around the turn of the century, the cooperation between the mission and the colonial government increased significantly. The introduction of Ethical Politics in 1901 strengthened the position of the missions. The year 1908 marked the beginning of the complete surrender of the Ono Niha to Western dominance, both physically and spiritually. The foundations of the primal religion had by now been seriously shaken. This, in addition to the yoke of colonialism, resulted in a spiritual vacuum in the communal psyche of the Ono Niha. The experience of total powerlessness triggered a crisis of identity. While not denying its religious factors, the outbreak of the Great Awakening at the end of 1915, must therefore be understood from a sociological perspective as a survival strategy. As well as being a spiritual revival, the Great Awakening was also an indigenous missionary movement. The Ono Niha ardently carried Christianity to the remotest of villages, while the missionaries anxiously tried to regulate and limit the scope of this dynamic movement. In this context, mention must be made of the key role played by the 'new' Niasan ministries, the sinenge and pandita, as well as that of women. Both the missionaries and the guru, who were paid by the government, were not very supportive of the Great Awakening. The most significant result of the awakening was that the primal religion, as an institutional system of beliefs, was shattered. Many Ono Niha experienced this as the birth of a new eschatological awareness. The conversion from belief in the ancestors (adu) to faith in Jesus Christ transformed the view of time and history from the traditional, cyclical world view with its golden era in the past to a linear view, with the Kingdom of God in the future. Nevertheless, the indigenous culture did strongly influence the form Christianity assumed among the Ono Niha. Clandestinely, under the cover of nominal Christianity, the values, worldview, and certain shamanistic practices of the primal religion continue to play a significant role in the lives of the Ono Niha. Today, as Christians all over Indonesia are struggling to relate the Gospel to their rapidly changing contexts, this study wants to offer a critical analysis of the missionary and ecclesiastical heritages on Nias and the Batu Islands, and suggest some steps towards a contextual theology for the Ono Niha.