Off Armageddon Reef
David Weber
 Humanity is at war with a genocidal alien race known as the Gbaba, and after a long war, it becomes obvious that humans are losing. In order to preserve the species, several colonization expeditions are sent out to other stars, but all are tracked down by the Gbaba. Finally, a colony fleet manages to sneak away via trickery. The passengers of the colony ships spend a decade in hyperspace in cryogenic sleep, and then arrive at a planet thousands of light years away from and slightly smaller than Earth, which they colonize and name Safehold. The original plan for this society was to wait for the immediate danger to pass, rebuild the technological base from records and artifacts left behind, and prepare a force large enough to defeat the Gbaba. However, the mission command is split into two groups. The first group is led by a Machiavellian administrator named Eric Langhorne. Langhorne believes that unless the humans in hiding on Safehold are permanently restricted to a Medieval level of technology, they will be eventually detected and destroyed by the Gbaba. During the trip to Safehold, the group alters the colonists' memories so they believe upon awakening they are the first humans and that they were created by a god. The radical leaders create a new religious institution called the Church of God Awaiting, which proscribes advanced technology and effectively deifies the members of mission command (they are hereafter called angels and are led by "Archangel Langhorne"). The second group, under the administrator Pei Shan-wei, wishes to preserve advanced technology and concepts, but not to use such knowledge until humanity is ready. In this way, the knowledge would be preserved and available for future generations. Once the human population had recovered, they could gradually ramp up the technology until they were capable of defeating the Gbaba. To this end, the second group establishes a city named Alexandria to house its members and technological information. The two groups break into open warfare, and Langhorne has the city of Alexandria, and all its inhabitants (including Shan-Wei, who is made into the Safeholdian version of Lucifer by the Church), destroyed by orbital bombardment. The city ruins and the surrounding land mass are sunk beneath the ocean, creating what the now-superstitious colonists call Armageddon Reef. In a counter-attack, Shan-wei's supporters manage to eliminate most, but not all of, Langhorne's inner circle, including Langhorne. Shan-wei's group also managed to hide an android, with the personality and memories of Nimue Alban, a dead female starship tactical officer, deep within a secret mountain base, along with technology, an electronic library and a room full of weapons. When Nimue awakes some 800 years later, the situation is explained to her by a recording created by Shan-Wei's now deceased husband, Pei Kau-yung, and she is offered the mission of reversing the plans of the radicals and helping prepare mankind for the inevitable re-encounter with the Gbaba on more favorable terms. Nimue accepts the mission and uses mobile spy technology to examine the world. However, it becomes clear that as an apparent woman, her influence would be less than it should be. She therefore changes into an apparent male and takes the name of Merlin before travelling to the Kingdom of Charis which is a relatively advanced region of Safehold with a somewhat free-thinking approach to religion. Merlin gains the trust of King Haarahld of Charis by interfering in an assassination attempt on Haarahld's son, Crown Prince Cayleb of Charis, saving his life. Merlin is made Cayleb's personal guardian and a de facto adviser to the king. He begins to introduce technology that, while not technically proscribed by the Safeholdian Bible, is advanced. While most of Safehold is at a 14th century level of technology, Merlin introduces better sailing vessels, improved gunpowder, and greatly improved seaborne cannons, very equivalent to the 17th century in Europe. Events come to a head when the Church organizes an attack on Charis by most of its neighbors. Largely due to the technology introduced by Merlin, the combined attacking fleets of galleys are annihilated by the small Charis fleet of heavily-armed galleons, although King Haarahld is killed in battle. The book ends at his funeral, about one month after the end of the battle, with Cayleb being crowned king without the Church's consent and with the beginning of a reformation movement emerging in Charis.