Off Armageddon Reef

Off Armageddon Reef is a science fiction novel by the American writer David Weber, published by Tor Books in 2007. It is the opening book of the Safehold series.

The survivors reach Safehold after barely escaping the Gbaba, the alien power that destroyed human civilisation and that hunts down emergency colonies by the traces of advanced technology they leave behind. Eight million people make the crossing. The plan drawn up for the new colony is to sit out the danger as a pre-industrial world, which means giving up the science that could reveal where they are. Langhorne, the administrator in charge, changes the plan: the colonists' memories are wiped and replaced with the belief that they are the first humans, made by God on Safehold, with Langhorne himself installed as the prophet of the Church of God Awaiting. Studying the wrong subject becomes heresy, and the novel follows what a society founded on that arrangement does with the people inside it.

Weber is known for long series built around military and political machinery, and Safehold is among the longest of them. The setting is unusual among his books because the technology problem runs the other way: instead of a protagonist reaching for better weapons, the world has been deliberately frozen at a medieval level, and the contest is between a church that enforces ignorance and anyone who wants to know what actually happened.