Let the first chamber of history therefore be that which stretches from the year 750 B.C. to the era of His Incarnation. I say 750 for the present, because it would be quite idle, in dealing with intervals of time so vast, to take notice of any little excess or defect by which the actual period differed from the ideal; strictly speaking, the period of authentic history commences sixteen or seventeen years earlier. But for the present let us say in round numbers that this period commenced 750 years B.C. And let the first chamber of history be of that duration. B. Next let us take an equal space _after_ Christ. This will be the second chamber of history. Starting from the birth of our Saviour, it will terminate in the middle of the eighth century, or in the early years of Charlemagne. These surely are most remarkable eras. C. Then passing for the present without explanation to the year 1100 for the first Crusade, let us there fix one foot of our 'golden compasses,' and with the other mark off an equal period of 750 years. This carries us up nearly to the reign of George III, of England. And this will be the third great chamber of history. D. Fourthly, there will now remain a period just equal to one-half of such a chamber, viz.: 350 years between Charlemagne's cradle and the first Crusade, the terminal era of the second chamber and the inaugural era of the third. This we will call the ante-chamber of No. 3. Now, upon reviewing these chambers and antechambers, the first important remark for the student is, that the second chamber is nearly empty of all incidents. Take away the migrations and invasions of the several Northern nations who overran the Western Empire, broke it up, and laid the foundations of the great nations of Christendom--England, France, Spain--and take away the rise of Mahommedanism, and there would remain scarcely anything memorable.