Cover art
Green, Roland J., and John F. Carr. Great Kings' War. Ace 1985.

Carr, John F., Roland J. Green, and Wolfgang Diehr. Lord Kalvan of Otherwhen Sequels
Series note: A series of sequels to the original Lord Kalvan of Otherwhen, by H. Beam Piper, q.v., which was a novel-length Paratime story. Includes Carr and Green's Great Kings' War, Carr's Kalvan Kingmaker, Carr's Siege of Tarr-Hostigos, Carr and Diehr's The Hos-Blethan Affair, Carr's The Fireseed Wars, Carr's Gunpowder God, and Carr's Down Styphon!
Web link: Hostigos.com

Carr, John F., and Roland J. Green. Great Kings' War
Divergence: c 2000 BCE
Summary: In their first attack on Lord (now King) Kalvan, Styphon's House hits back with three forces, but is defeated in all cases.
Series note: First sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Published: Ace 1985 (0441302009BUY), as by Green and Carr.
— Revised edition, as by Green and Carr, posted on-line at Baen Free Library, Oct. 1, 2004.
— Revised and expanded edition, as by Carr and Green, Pequod 2006 (0937912034BUY).
Web link: Baen Free Library

Cover art
Carr, John F. Kalvan Kingmaker. Pequod 2004.

Carr, John F. Kalvan Kingmaker
Divergence: c 2000 BCE
Summary: Styphon's House drives barbarians from the North American plains east into Kalvan's territory in order to destroy him, but he turns the tables on them.
Series note: Second sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Published: Pequod 2001 (0937912018BUY).
Published: Expanded from "Kalvan Kingmaker", as by Carr and Roland J. Green, in Alternatives (eds. Robert Adams and Pamela Crippen Adams), q.v.

Cover art
Carr, John F. Siege of Tarr-Hostigos. Pequod 2004.

Carr, John F. Siege of Tarr-Hostigos
Divergence: c 2000 BCE
Summary: Lord Kalvan loses his citadel to the forces of Styphon's House.
Series note: Third sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Published: Pequod 2004 (0937912026BUY), rev. 2012.
— Expanded from "Siege at Tarr-Hostigos", as by Roland J. Green and Carr, in There Will Be War 8: Armageddon (eds. Jerry Pournelle and John F. Carr), Tor 1989 (0812549651BUY).

Carr, John F., and Wolfgang Diehr. The Hos-Blethan Affair
Series note: Fourth sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Comments: Although published after Gunpowder God, this volume is roughly contemporaneous with Siege of Tarr-Hostigos.
Published: Pequod 2014 (0937912638BUY).

Carr, John F. The Fireseed Wars
Divergence: c 2000 BCE
Series note: Fifth sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Published: Pequod 2010 (0937912050BUY).
Publication note: Known during development by various titles, including Queen Rylla's Crown, Queens Rylla's Victory, and Queen Rylla's Throne. May have briefly been called Gunpowder God; but if so, that title was instead later applied to the next book in the series.

Carr, John F. Gunpowder God
Divergence: c 2000 BCE
Series note: Sixth sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Comments: Note that "Gunpowder God" was the title of the novella that made up the first half of Lord Kalvan of Otherwhen, q.v., and which was used as the title for one British edition of Lord Kalvan.
Published: Pequod 2012 (0937912158BUY).

Carr, John F. Down Styphon!
Divergence: c 2000 BCE
Series note: Seventh and apparently final sequel to H. Beam Piper's Lord Kalvan of Otherwhen, q.v.
Comments: Note that "Down Styphon" was the title of the novella that made up the second half of Lord Kalvan of Otherwhen, q.v.
Published: Pequod 2016 (0937912670BUY).