The Trumpets of Mars (Imperium, #2)

Marching to War
The Carthaginians are marching to destroy Rome and it is up to Ky, a test pilot from the future thrown into an alternate past, to keep the once mighty Roman Empire from being destroyed. As Ky gathers Roman forces to defend against the Carthaginian host, he must also struggle to contend with a malfunctioning AI implanted in his brain that is slowly gaining sentience. Thankfully, he is not alone. With the help of the Emperors daughter Lucilla, he fights both his own mind and the Carthaginian hordes for a chance to build a new world.