Already by April 18 a part of the Outer Wall and even two great towers of the Inner had been broken down in the Lycus valley.[282] Justiniani had been compelled to take in hand the construction of a stockade for their defence ‘where the attack was the fiercest and the damage to the walls the greatest.’ The walls of the foss, including the breastwork, had been broken down, the foss itself in this place partly filled. The wonderful success already achieved by his great guns led Mahomet to believe that he could already capture the city. Accordingly, at two hours after sunset on April 18 he gave orders for the first time to attempt the city by assault. [Sidenote: Attempt to capture city by assault on April 18 fails.] Infantry, cuirassiers, archers, and lancers joined in this night attack. They crossed the foss and vigorously attempted to break through or destroy the Outer Wall. They had observed that in the repairs the besieged had been driven to employ beams, smaller timber, crates of vine cuttings, and other inflammable materials. These they attempted to set on fire; but the attempt failed. The defenders extinguished the fires before they could get well hold. The Turks with hooks at the end of lances or poles then tried to pull down the barrels of earth which had been placed so as to form a crenellation and in this way to expose the defenders to the attacks of the archers and slingers. Others endeavoured to scale the hastily repaired and partially destroyed wall. During four hours Justiniani led his Italians and Greeks in the defence of the damaged part, and after a hard conflict the Turks were driven across the foss with a loss in killed and wounded estimated by Barbaro at two hundred. The attack was local and not general, though Barbaro remarks that the emperor began to be in doubt whether general battle would not be given on this night, and ‘we Christians were not yet ready for it.’ The failure of this the first attack stimulated Greeks and Italians to press on the repairs to the Outer Wall. Every day, however, there were new assaults made at one place or another, but especially in the Lycus valley. [Sidenote: Attempt to force boom.] A few days after the return of Baltoglu with the fleet from Prinkipo, and probably contemporaneously with the attack in the Lycus valley on the 18th, the admiral was ordered to force a passage into the Golden Horn.