The Hammer — S.M. Stirling; David Drake

Raj Whitehall's army faces hostile seas, heavy odds, and a legacy of disaster; but the computer in Raj's mind is God--and God is on their side....

A pre-Collapse computer is using General Raj Whitehall to reunite the planet awl to start Man's return to technological civilization across the whole galaxy. Raj is willing--but to be able, he must overcome the muskets and sabers of the barbarians in front of him; cowardice and envy among his own officers; and, in the court he serves, the grasping officials of an emperor likely to view success as treason. Whether Raj succeeds or fails, there will be a bloodbath like no other before on the surface of the world.