David Drake, Book of The General II.-V.: The Hammer + The Anvil + The Steel + The Sword

The first five books are set on the planet Bellevue, previously part of a high-technology galactic civilization (the Federation). Interstellar civilization collapsed during "The Fall", when extensive civil war greatly reduced the planet's technology level. Technology has redeveloped only slowly: the most advanced groups have reached the level of double-expansion steam engines, wrapped-brass-cartridges breech-loading rifles (Martini-Henry lock or very similar) and lever-action carbines, cast-steel breech-loading cannon, simple revolvers, etc. Progress is slow: the breech-loading rifle design has not changed for over two hundred years, and other groups still use flintlock or percussion cap weapons.

The concept of computer technology has become the basis of religion throughout the world, the Spirit of Man, with priestly Hierarchs, Sysups, and an Inquisition called the Anti-Viral Cleansers. This religion is split into two competing sects: The Spirit of Man of the Stars, the state religion of the Civil Government, and Spirit of Man of This Earth, which is more popular among the barbarian Military Governments. The people of Bellevue speak various evolved dialects, including Sponglish, Spanjol, Namerique and Paytoiz, with elements of English, French and Spanish apparent. At the time of the Fall the planet had no horses, so now cavalry is mounted on thousand-pound dogs of various breeds.

The books begin in the Year of the Fall 1103, when the protagonist Raj Whitehall and his friend Thom Poplanich stumble on a still-working remnant of the old technology, the quantum supercomputer "Center", which Raj and Thom regard as an angel. Center describes itself as a "sentient artificial entity of photonic subsystems tasked with the politico-military supervision" of Bellevue. Center charges Whitehall with uniting Bellevue and provides him, through a constant mental link, with predictive visions that simulate probable situational outcomes, historical data, eidetic memory, and minor enhancements to physical abilities including accuracy with firearms. Raj couples these assets with his own charisma and skill to become an extremely effective military leader. Meanwhile, his wife Suzette quietly uses her own highly developed court intrigue skills to neutralize Raj's political foes and obstacles behind the scenes, compensating for his more direct tactics.

Center keeps Thom in suspended animation within its sanctum, explaining that he will otherwise probably be the victim of political assassination before long, and begins to educate him in matters more related to civil administration. As Raj acknowledges (and Center's projections confirm), he would not be an effective civilian leader, but Thom—the legitimate heir, with the assistance of Raj and Center—will.

True to their historical model, the campaigns of Belisarius, the books focus on the convoluted "strategic offensive, tactical defensive" campaigns of General Whitehall around the Midworld Sea and his fraught relationships with his paranoid but capable 'emperor' –- Governor Barholm Clerett—and Clerett's avaricious and corrupt chancellor Tzetzas.

Whitehall's nation calls itself the Civil Government, and it is centrally located between the rival nations of the Military Governments—The Brigade and The Squadron—and the Muslim Colonists.