How Firm a Foundation by David Weber
The Charisian Empire, born in war, has always known it must fight for its very survival. What most of its subjects don't know even now, however, is how much more it's fighting for. Emperor Cayleb, Empress Sharleyan, Merlin Athrawes, and their innermost circle of most trusted advisers do know. And they know if they lose it will be far worse than their own deaths and the destruction of all they know and love. For five years, Charis has survived all the Church of God Awaiting and the corrupt men who control it have thrown at the island empire. The price has been high and paid in blood. Despite its chain of hard-fought naval victories, Charis is still on the defensive. It can hold its own at sea, but if it is to survive, it must defeat the Church upon its own ground. Yet how does it invade the mainland and take the war to a foe whose population outnumbers its own fifteen to one? How does it prevent that massive opponent from rebuilding its fleets and attacking yet again? Charis has no answer to those questions, but needs to find one...quickly.