By Blood Divided

Siward, scion of a great dynasty, commands the Varangian Guard and has vowed to defend the Roman Empire to the last. Makkim, renowned general to Ottoman rule, has vowed to destroy it.
They are enemies in war, but unknown to them, they are also rivals to inherit one of Europe's greatest fortunes. Even worse, they are competing for the love of the same woman. Their vast inheritance lies in Venice, as does the famous courtesan they both love. She is the reason they will find themselves fighting on the walls of Constantinople, in one of the most dramatic sieges in history.