History, in the broadest sense of the word, is all that we know about everything that man has ever done, or thought, or hoped, or felt. It is the limitless science of past human affairs, a subject immeasurably vast and important but exceedingly vague. The historian may busy himself deciphering hieroglyphics on an Egyptian obelisk, describing a mediæval monastery, enumerating the Mongol emperors of Hindustan or the battles of Napoleon. He may explain how the Roman Empire was conquered by the German barbarians, or why the United States and Spain came to blows in 1898, or what Calvin thought of Luther, or what a French peasant had to eat in the eighteenth century. We can know something of each of these matters if we choose to examine the evidence which still exists; they all help to make up history. One who undertakes to condense what we know of Europe’s past, since the times of Theodosius and Alaric, into the space of six hundred pages assumes a very grave responsibility. The reader has a right to ask not only that what he finds in the book shall be at once true and clearly stated, but that it shall consist, on the whole, of the most important and useful of all the things which might have been selected from the well-nigh infinite mass of true things that are known...