The appeals to the Western Powers resulted in a certain, but very insufficient, number of volunteers from Southern Europe giving their services to support the Greek cause in its final struggle with the Moslems. Seven hundred Genoese came under the command of Giustiniani, an able soldier of fortune, who proved to be the main support of Constantine. Others had come with Cardinal Isidore, at the instance of the Pope, and with some small amount of money from the same quarter. There were Catalans and Aragonese from Spain, but the number of these recruits from Western Europe did not exceed three thousand. The total force under the command of Constantine for the defence of the city amounted to no more than eight thousand. It is strange that there were no volunteers from France and Germany, or from Hungary and Poland, from whence so many crusaders had volunteered in previous years to drive the Turks out of Europe. Nor was there any valid assistance in men and money from the numerous Greeks in the Levant. The unfortunate Constantine was not only very deficient in men, but his resources in money were very low. He had, however, in his service twenty powerful galleys well manned, and three galleys had come from Venice. It would seem that the cause of Constantine did not much interest Europe, and did not even meet with an effective support among the Greeks themselves. The city of Constantinople, as it then existed, was situate between the Golden Horn, its great harbour, and the sea of Marmora. Its land frontage, distant about nine miles from the entrance to the harbour, was four miles in length. It was protected by a triple line of walls, the two inner of which were very massive, flanked by towers at distances of 170 feet. There was a space of 60 feet between these walls. The third and outer wall was a crenelated breastwork on the other side of a fosse, of a width of 60 feet. This powerful line of defence had been devised by the Emperor Theodosius II about a thousand years ago and had protected the city in twenty sieges. Before the invention of cannon it was practically impregnable.[17] There were also fortifications extending for about nine miles on the side of the Golden Horn. The eight thousand men were too few even for effective defence of the four miles of walls, which were to be attacked directly by the Ottoman army, to say nothing of the fortifications along the side of the Golden Horn. The defence, however, with these limited means, was a spirited one. It showed that if the Greek Emperor had been adequately supported by the Western Powers Mahomet might not have been able to capture the city.