This History of the Reformation has been written with the intention of describing a great religious movement amid its social environment. The times were heroic, and produced great men, with striking individualities not easily weighed in modern balances. The age is sufficiently remote to compel us to remember that while the morality of one century can be judged by another, the men who belong to it must be judged by the standard of their contemporaries, and-not altogether by ours. The religious revival was set in a framework of political, intellectual, and economic changes, and cannot be disentangled from its surroundings without danger of mutilation. All these things add to the difficulty of description. My excuse, if excuse be needed, for venturing on the task is that the period is one to which I have devoted special attention for many years, and that I have read and re-read most of the original contemporary sources of information. While full use has been made of the labours of predecessors in the same field, no chapter in the volume, save that on the political condition of Europe, has been written without constant reference to contemporary evidence.