My Border, My Army, My Empress

Five years into Raymond's posting on the northern frontier, an empress arrives in his county with her small daughter, looking for family. The two of them have met before. She stays on, and something starts between them while she watches how he runs the place. Raymond had come into this world from a modern one and been made magistrate of Beiliang, a border county with little in it. He put what he knew to use, bringing in technology the place had never had and rebuilding the army around it, and he drilled the men himself. Raiders who came over the border were pushed back each time they tried. His command grew until it ran to a million men. That growth makes the other powers of the empire nervous. Revolts break out, and Raymond and the empress deal with them together.