Though the two magnificent Theodosian walls were as well constructed as elsewhere, and to the eye of an ordinary observer the city was as strongly protected in the Lycus valley as anywhere, yet this place appears to have been considered by many of the enemies of the city as its weakest point. Here, says Dethier, with whom Professor Van Millingen agrees, was the Heel of Achilles.[245] Many previous invaders, ending with Murad in 1422, had encamped in the Mesoteichion as the most suitable position for an attack upon the city.[246] The accompanying sketch of the walls will show their general plan. Under normal conditions a large detachment of the defenders of such high lines of walls ought to have been on the city side of the great Inner Wall. So few, however, were the besieged, that all had to pass into the enclosures to meet the enemy at the second or Outer Wall. Partly because of the small number of men, but partly also because it had been allowed to get out of repair,[247] the Inner Wall, which, as the highest and strongest, ought to have been the most serious obstacle, was hardly relied upon as a means of defence. Chalcondylas says[248] that the emperor and the leading Greeks deliberated as to where the enemy was to be resisted, and that they decided that they should defend the Outer Wall, which was strengthened by the foss in front of it, as had been done when Murad had attacked the city thirty-one years before. Leonard expressly states that the imperial troops were sufficient to guard only the Outer Wall, and the stockade which, at a late period of the siege, replaced a portion of it. As his own countrymen took part in this task, his testimony is entirely credible.[249] He adds, however, that in his opinion this plan of defence was a blunder; that he was always persuaded that the lofty Inner Wall ought to have been kept ready as a refuge in case of retreat; that those walls which, through neglect or hard weather, had become broken or useless for operations against the enemy, might have been repaired even within the time which elapsed between the proposal for war and the commencement of the siege. Had they been repaired and guarded, they would have provided a reserve of safety to the city. It is when regretting that these repairs were not undertaken that, while excusing the emperor, Leonard breaks out into indignation, justifiable if his belief was well founded[250] against two persons in particular, Jagarus and a monk named Neophytus who had embezzled the moneys which had been bequeathed for the repair of the walls, and declares that the city was lost through the rascality of public robbers. Through their dishonesty, the besieged were driven to place all their hope in the Outer Wall and the foss. The Jews, he adds, were more prudent who when, at the siege of Jerusalem, they were defeated at the first wall, retreated to the second, and then to the third, by which they prolonged the siege of Vespasian and Titus for four years.