You've found the home of Thomas Harlan's OATH OF EMPIRE series from Tor Books, which includes The
Shadow of Ararat, The
Gate of Fire, The Storm
of Heaven and The
Dark Lord.
And The Time of the Sixth Sun,
which is a science-fiction / archaeological-mystery/ space warfare epic
set in a far-future dominated by the Méxica (Aztec) Empire,
which currently includes Wasteland
of Flint, House of Reeds
and Land of the Dead.
This series is also published by Tor Books.
And... Crusader
Earth, which is a D20-system role-playing universe set on
historical Earth in the 1100's, mostly centered in the Holy Land and
Nabatea. Most of the components of this universe have been published in
DRAGON and DUNGEON magazines, published by Paizo Publishing.