It was long one of the strongest defences of the city, an almost impregnable acropolis, as Cantacuzene calls it. When the city was captured by the Turks, Mohammed II. increased the defences by building here, in 1457, behind the gate, the great enclosure now called the Seven Towers, which became the state prison. In it foreign ambassadors were placed when their countries were at war with Turkey, and there as late as the war with Revolutionary France a French ambassador was confined. Mohammed II. built up all the entrances of the Golden Gate; and the legend still survives that through it a victorious Christian army shall enter when the city is captured from the Turks. The gate nearest to it, now called Yedi Koulé Kapoussi, may probably have existed in Byzantine times, as a public gate called by the same name as the greater gate. Through it doubtless Basil the Macedonian came when he turned aside and lay down to sleep on the steps of the monastery of S. Diomed. Next to this as we walk northwards comes the second military gate, and, after walls which have several inscriptions, the second public gate, the Selivri Kapoussi (gate leading to the Selivria road). This was originally the πύλη τῆς πηγῆς, gate of the Holy Spring, which is at the village now called Balukli. After we have looked on it, with its old towers and dark narrow entrance through which Alexius the general of Michael Palæologus entered in 1261, it is delightful to turn aside and follow the shady road half a mile to the little Christian village, best of all if it is _en fête_ in the week of the Greek Easter, when you can buy icons and sacred medals, and join the crowds who throng the church and descend the steps by the baptistery to the sacred well. The legend of its sacredness goes far back. As early as Justinian's time there was a church there, as Procopius says, "in the place which is called the Fountain, where there is a thick grove of cypress trees, a meadow whose rich earth blooms with flowers, a garden abounding with fruit, a fountain which noiselessly pours forth a quiet and sweet stream of water--in short, where all the surroundings befit a sacred place." There was also for many centuries a palace and park of the Emperors. The last tale of the sacred well belongs to the time of the Turkish conquest. On the fatal 29th of May the village priest was sitting in his garden beside the well frying his fish, when a messenger rushed up with the news that the Turks had broken through the wall and were entering the city. The holy man refused to believe it. "But run to the top of your garden," said his friend, "and see for yourself." "No. I would as soon believe that these fish should leap out of the frying-pan into the spring." And they did; and there are their descendants, as any one may see for himself, to this day.