Of course all the churches of the city were never contemporaneous. In a city which had a life of more then eleven centuries, the list of almost any class of edifices erected in the course of that period would necessarily be a long one, without implying the existence of numerous edifices of that class at one and the same time. According to the description of Constantinople which dates from the first quarter of the fifth century, the number of churches then in the city is given as only fourteen. Churches appeared and disappeared, and while some of them were, for special reasons, maintained throughout the whole course of the city’s history, many came to flourish for a while and then decayed in the ordinary course of things, bequeathing as their memorial only the withered leaves of their names. Then we must remember the frequent and disastrous earthquakes which shook the soil of Constantinople during the Middle Ages, and the terrible conflagrations which again and again reduced the wealth and glory and beauty of extensive tracts of the city to dust and ashes. For example: the three fires associated with the capture of the city by the Latins in 1203-1204 inflicted a blow from which the city never recovered. One of those fires raged for a night and a day; another for two days and two nights, with the result that almost all the territory along the Golden Horn, as well as the territory extending thence to the Hippodrome and the Sea of Marmora, as far away as Vlanga, were turned into a wilderness of smoking ruins. “The fire,” says Ville-Hardouin, a spectator of the awful scene, “was so great and so terrible that no man could extinguish or check it. It was a sad and pitiful spectacle for the barons of the army encamped on the other side of the harbour to see those beautiful churches and those rich palaces fall in and be destroyed, and great business streets burned by the scorching flames; but they could do nothing. The fire spread beyond the harbour across to the densest part of the city, quite close to S. Sophia, and as far as the sea on the other side. It lasted two days and two nights, without being ever touched by the hand of man, and the front of the fire was fully half a league long. Of the damage done, or of the property and wealth thus lost and consumed no estimate can be made, nor of the number of men, women, or children who perished.” It is true that churches injured by the hand of time were often restored. There were even periods when such renovation was carried out on an extensive scale, as for instance under Justinian the Great and under Basil I. (867-886). But not less frequently the old fabric was so weakened by age or shaken by earthquake that to repair it was out of the question, and the only thing to be done was to use its stones and bricks and marbles as materials in the construction of other buildings. Much of the material, for instance, employed in the erection of the Tower of Isaac Angelus, in front of the Palace of Blachernæ, was taken from the ruins of old churches. While for the construction of the citadel which John VI. Palæologus (1341-1391) built near the Golden Gate, material was taken from the remains of churches so noted in their day as the Church of All Saints, the Church of the Forty Martyrs, and the Church of S. Mokius.