Evangelism
- In S. M. Stirling's Nantucket series, the entire island of Nantucket is suddenly transported into the past, to about 1300 B.C, and the modern Americans marooned in the past must make the best of the Bronze Age world in which they find themselves. The Christians among them face the dilemma of whether or not to embark on missionary activity and spread their religion - even though Jesus Christ had not yet been born, and the very act of their spreading Christianity might so fundamentally change the world that Jesus would never be born at all.
- In The Sparrow, by Mary Doria Russell, Jesuit missionaries are sent to investigate a radio transmission from an unknown planet, believing that they have been chosen by God to be the first to step foot on an alien world. Most of them are killed by the planet's inhabitants, and the sole survivor is enslaved. He finally escapes and returns to Earth with his faith in tatters.
Read more about this topic: List Of Religious Ideas In Science Fiction