One thousand years ago, the Normans enjoyed a brief moment of ascendancy. In that time, they emerged from their duchy in northern France to lead a remarkably successful crusade to the Holy Land, establish a kingdom in Sicily and southern Italy that left some of the great religious monuments of the era, and, of course, conquer the British Isles. Legends abound of their exploits, which has given rise to a historical reputation of them as a master race of uniquely skilled warriors descended from the Vikings and favored by God. This book argues that they were, instead, lucky opportunists who took advantage of transient geopolitical power vacuums. The Roman Catholic Church was on the rise, military technology was changing, monarchs and bureaucrats were forging modern state administrations, and nobles were reviving large-scale architectural projects. It was a moment when a small and ruthless band of well-commanded fighters with siege technology and powerful ecclesiastical connections could make a mark—and the Normans were at the right place at the right time to benefit. Yet their triumph would be short-lived: within a century, larger European states and empires would copy their innovations and reconquer most of their lands.