In the mid-sixth century, the Byzantine emperor ruled a powerful empire that spanned regions of Europe, Asia, and North Africa. Within a hundred years, this formidable empire had lost half of its territories.

Two centuries later, the Byzantine Empire had once again dynamically returned to the forefront as a dominant power in the Eastern Mediterranean and the Balkan Peninsula, the mythical wealth of which attracted mercenary Vikings and nomadic warriors from the steppes of Central Asia to its armies. The mere appearance of these troops on the battlefield instilled awe and panic, leading enemies to immediate retreat and negotiations.

The Byzantine Empire remains enigmatic for today's average reader, if for no other reason, at least for the dramatic fluctuations in its political fortunes and its romantic end in 1453, when the last emperor, Constantine XI Palaiologos, was killed at its walls in a battle to the last against the elite Ottoman troops of the janissaries who invaded besieged Constantinople, a city that, throughout its millennium-long history, had never been captured by direct assault.