4. Now as the Romans began to raise their banks on the twelfth day of the month Artemisius, [Jyar,] so had they much ado to finish them by the twenty-ninth day of the same month, after they had labored hard for seventeen days continually. For there were now four great banks raised, one of which was at the tower Antonia; this was raised by the fifth legion, over against the middle of that pool which was called Struthius. Another was cast up by the twelfth legion, at the distance of about twenty cubits from the other. But the labors of the tenth legion, which lay a great way off these, were on the north quarter, and at the pool called Amygdalon; as was that of the fifteenth legion about thirty cubits from it, and at the high priest's monument. And now, when the engines were brought, John had from within undermined the space that was over against the tower of Antonia, as far as the banks themselves, and had supported the ground over the mine with beams laid across one another, whereby the Roman works stood upon an uncertain foundation. Then did he order such materials to be brought in as were daubed over with pitch and bitumen, and set them on fire; and as the cross beams that supported the banks were burning, the ditch yielded on the sudden, and the banks were shaken down, and fell into the ditch with a prodigious noise. Now at the first there arose a very thick smoke and dust, as the fire was choked with the fall of the bank; but as the suffocated materials were now gradually consumed, a plain flame brake out; on which sudden appearance of the flame a consternation fell upon the Romans, and the shrewdness of the contrivance discouraged them; and indeed this accident coming upon them at a time when they thought they had already gained their point, cooled their hopes for the time to come. They also thought it would be to no purpose to take the pains to extinguish the fire, since if it were extinguished, the banks were swallowed up already [and become useless to them].