In 1095, with the tomb of Jesus still in the hands of infidels and the Byzantine empire overrun by Muslim Turks, Pope Urban II summoned Christian warriors to take up the cross and their swords against the Turks and then recover the holy city of Jerusalem from Islam. It was to be the first of the Crusades, a holy war that would focus the power of the European kingdoms against a common enemy. The Crusades became the stuff of romantic legend, but in reality they were a series of rabidly savage battles carried out in the name of Christian piety to advance the power of the Western Church. Their legacy of religious violence is felt today as the age-old conflict of Christians, Jews, and Muslims persists.

Karen Armstrong, the bestselling author of A History of God, enters the minds of kings and sultans, popes, saints, assassins, and simple pilgrims, skillfully presenting the Crusades from the perspective of all three traditions and with a view toward their profound and continuing influence.