Cover art
Harlan, Thomas. The Shadow of Ararat. Tor 1999 (cover art by Stephen Hickman).

Harlan, Thomas. The Oath of Empire
Divergence: 27 BCE
What if: The Roman Empire was protected by magic wrapped into the oath of allegiance first sworn during the reign of Augustus.
Summary: Set in the 7th century (CE) of a Rome which never fell.
Series note: Four-volume series, including The Shadow of Ararat and The Gate of Fire, The Storm of Heaven, and The Dark Lord.
Web link: Harlan's Throne World

Harlan, Thomas. The Shadow of Ararat
Divergence: 27 BCE
Summary: The Eastern and Western Roman Empires join together for an all-out assault on Persia. Meanwhile, a younger brother of the Western Caesar delves into dark magics to discover the source of a longstanding curse on Rome and a Persian dark lord begins amassing power.
Series note: First volume of The Oath of Empire.
Published: Tor 1999 (0312865430BUY), 2000 (0812590090BUY).
Original in: English.
Translation: French in two volumes by Michele Zachayus as L'ombre d'Ararat, Fleuve Noir 2000 (2265069949); and Les cléfs de pouvoir, Fleuve Noir 2000 (2265069957).
Translation: Polish by Janusz Ochab as Cien Araratu, Prószýski I S-Ka 2005.

Cover art
Harlan, Thomas. The Gate of Fire. Tor 2000 (cover art by Stephen Hickman).

Harlan, Thomas. The Gate of Fire
Divergence: 27 BCE
Summary: As rebellion begins in Arabia due to the Roman betrayal of Palmyra and as dark forces arise in the ruins of Persia, the work of a Roman prince edges into potential treachery against the empire and his once-allies must decide whether he must destroyed.
Series note: Second volume of The Oath of Empire.
Published: Tor 2000 (0312865449BUY), 2001 (0812590104BUY).
Original in: English.
Translation: Polish by Janusz Ochab as Brama Ognia, Prószýski I S-Ka 2006.

Cover art
Harlan, Thomas. The Storm of Heaven. Tor 1999 (cover art by Stephen Hickman).

Harlan, Thomas. The Storm of Heaven
Divergence: 27 BCE
Series note: Third volume of The Oath of Empire.
Published: Tor 2001 (0312865597BUY), 2002 (0812590112BUY).
Original in: English.
Translation: Polish by Janusz Ochab as Burza Niebios, Prószýski I S-Ka 2008 (8374697865).

Cover art
Harlan, Thomas. The Dark Lord. Tor 2002 (cover art by Stephen Hickman).

Harlan, Thomas. The Dark Lord
Divergence: 27 BCE
Series note: Fourth and final volume of The Oath of Empire.
Published: Tor 2002 (0312865600BUY), 2003 (0812590120BUY).