The condition of Constantinople at the beginning of the thirteenth century has been the subject of more than one exhaustive examination. We must briefly summarise what is known of the capital at this period of its greatest riches, and perhaps its greatest weakness. First and most prominently, it was a great commercial centre. Subordinate to its commerce were its art, rich and wonderful though that was, its military power, even its popular and all-embracing religious spirit. Commerce influenced all these. It gathered together all the nations of the earth, and it inspired them with greed for its treasures. Constantinople was, as it still is to some extent, in spite of the revolutions wrought by railways and by steamships, the most important outlet of commerce in the world. All the traffic of Asia naturally came that way; the great caravans of Central Asia, the trade of Palestine, Asia Minor, Persia, even Egypt, journeyed naturally to the New Rome. So naturally was Constantinople the centre of trade that she acted as a sort of universal banker. Her coins were in use in India and in distant England. And the merchants who made their living in Constantinople had, like those of the Hansa in London, their own permanent settlements. You may see to-day the great khans or caravanserais where the merchants and pilgrims congregate, the walls strong to resist attacks, the gates closed at nightfall, the arrangements for common meals and common ablutions; and as you pass by you see the dark figures clustering in the doorways, or sitting on the marble steps, in their picturesque colours, and with that strange far-away look on their faces that you learn to know so well in the land where there is never any more pressing need than repose, or any delight more sweet. The custom of these great common lodgings, and very often the buildings themselves, go back far into the Middle Ages. In the thirteenth century they held great colonies of merchants strong for mutual combination and defence. Many of them were near to the wharves, as close within the walls as might be, and some without. No visitor to-day can fail to be struck by the great khan hard by the Mosque of Validè Sultan, which he passes when he has crossed the Galata Bridge on his way to S. Sophia.