Complex sentence: The Congregational Christian Church in Samoa was started by the London Missionary Society, especially the arrival of Rev. John Williams played an important role in the birth of the denomination, accompanied by missionaries from Tahiti, the Cook Islands and Tonga.
Split into simpler sentences: The Congregational Christian Church in Samoa was started by the London Missionary Society. The arrival of Rev. John Williams played an especially important role in the birth of the denomination, accompanied by missionaries from Tahiti, the Cook Islands and Tonga.