We must learn, above all, to study sympathetically institutions and beliefs that we are tempted at first to declare absurd and unreasonable. The aim of the historian is not to prove that a particular way of doing a thing is right or wrong, as, for instance, intrusting the whole government to a king or forbidding clergymen to marry. His object is to show as well as he can how a certain system came to be introduced, what was thought of it, how it worked, and how another plan gradually supplanted it. It seems to us horrible that a man should be burned alive because he holds views of Christianity different from those of his neighbors. Instead, however, of merely condemning the practice, we must, as historical students, endeavor to see why practically every one in the thirteenth century, even the wisest and most tender-hearted, agreed that such a fearful punishment was the appropriate one for a heretic. An effort has, therefore, been made throughout this volume to treat the convictions and habits of men and nations in the past with consideration; that is, to make them seem natural and to show their beneficent rather than their evil aspects. It is not the weakness of an institution, but the good that is in it, that leads men to adopt and retain it. [Sidenote: Impossibility of dividing the past into clearly defined periods.] [Sidenote: All general changes take place gradually.] 2. It is impossible to divide the past into distinct, clearly defined periods and prove that one age ended and another began in a particular year, such as 476, or 1453, or 1789. Men do not and cannot change their habits and ways of doing things all at once, no matter what happens. It is true that a single event, such as an important battle which results in the loss of a nation's independence, may produce an abrupt change in the government. This in turn may encourage or discourage commerce and industry and modify the language and the spirit of a people. Yet these deeper changes take place only very gradually. After a battle or a revolution the farmer will sow and reap in his old way, the artisan will take up his familiar tasks, and the merchant his buying and selling. The scholar will study and write and the household go on under the new government just as they did under the old. So a change in government affects the habits of a people but slowly in any case, and it may leave them quite unaltered.