The city soon became worthy to be the seat of empire. It commanded from its seven hills the opposite shores of Asia and Europe. The climate was healthy, the soil fertile, and the harbour capacious and secure. The Bosphorus and the Hellespont were its two gates, which could always be shut against a hostile fleet. A hundred years after its foundation, a writer, quoted by Gibbon, describes it as possessing a school of learning, a circus, two theatres, eight public and a hundred and fifty-three private baths, fifty-two porticos, five granaries, eight aqueducts, four spacious halls for the meetings of the senate and courts of justice, fourteen churches, fourteen palaces, and four thousand three hundred private houses, which from their size and beauty deserved to be distinguished from the multitude of plebeian buildings. Successive wars and invasions impaired the wealth and the magnificence of the city. Of the time of Constantine little remains but the ruins of the Hippodrome. The Christian Church of St. Sophia, which he erected to the Eternal Wisdom, and from the pulpit of which Gregory of Nazianzen and Chrysostom the golden-mouthed thundered, was burnt in the reign of Justinian, and his Church of St. Sophia is now a Turkish mosque. The city was the seat and centre of the controversies originated in Alexandria as to the nature of the Trinity, and its rival factions, the Greens and the Blues, were ever ready to engage in bloody and disastrous conflict. As a rule, a man’s zeal is according to his ignorance, and at Constantinople the meanest mechanics spent most of their time in discussing mysteries of which the acutest intellects can never even form an adequate idea, and which no human creed can properly define and express. The Crusaders, who knew little of these matters, seem to have been quite awestruck when they made their way to Constantinople. ‘That such a city could be in the world,’ writes one of the old chroniclers, ‘they had never conceived, and they were never weary of staring at the high walls and towers with which it was entirely compassed; the rich palaces and lofty churches, of which there were so many that no one could have believed it if he had not seen with his own eyes that city—the queen of all cities.’