This book is about success: about Christianity's rise to power and its growth over two millennia to become the largest religion in the world today. It is also about failure: about Christianity's loss of influence in modern times and the precipitous decline in churchgoing that has taken place in many parts of the west since the 1960s.

In order to understand these mixed fortunes this volume considers the development of Christianity over two thousand years. It focuses on the changing relations between Christianity and society and looks, in particular, at the ways in which Christianity has related to power. It considers how Christian institutions and individuals have understood, articulated and embodied power, and how they have related themselves to political, economic, cultural and military power. Above all, the book considers Christian history in terms of two competing models of power – power from on high and power from below – and the consequences of the churches' tendency to favour the former over the latter.

The volume is divided into two parts, with a hinge in the sixteenth century. The first traces the way in which Christianity in the pre-modern period established itself as a major power first in the near east and then, increasingly, in the west. It shows that its success was due in large part to the way in which the Catholic version of Christianity was able to adopt and embody power from on high and form alliances with secular powers operating according to the same model.