In the 6th century AD, the Near East was divided between two great empires: the Persian and the Roman. A hundred years on, and one had vanished forever, while the other was a dismembered, bleeding trunk. In their place, a new superpower had arisen: the empire of the Arabs. So profound was this upheaval that it spelled, in effect, the end of the ancient world.

But the changes that marked the period were more than merely political or even cultural: there was also a transformation of human society with incalculable consequences for the future. Today, over half the world’s population subscribes to one of the various religions that took form during the last centuries of antiquity. Wherever men or women are inspired by belief in a single god to think or behave in a certain way, they bear witness to the abiding impact of this extraordinary, convulsive age.

In the Shadow of the Sword explores how a succession of great empires came to identify themselves with a new and revolutionary understanding of the divine. It is a tale vivid with drama, horror and startling achievement. But there are questions as well as stories. When did Judaism and Christianity finally and definitively split from one another? Where did Islam originate: in the depths of the desert or much further to the north? Are the claims made to this day by Jews, Christians and Muslims about the origins of their faiths all of them actually true?

http://www.tom-holland.org/books/in-the-shadow-of-the-sword/