The construction of the former banks had cleared all the timber from the immediate vicinity of Jerusalem, so that the Romans were compelled to go farther afield, and at the end of twenty-one days--the time taken in raising these new aggeres--there was not a tree left within ten miles of the city! Meanwhile, long teams of oxen, bellowing under the lash, were toiling up the rugged pass of Beth-horon, drawing endless files of wagons roped to each other, upon which were mounted the new military machines, huge and terrible, constructed by the Greek engineers of Cæsarea. On the twenty-second day, the artillery (this word is long anterior to the use of firearms) was placed in position, and the legions, massing all their strength, directed a fierce attack upon the northern wall of Antonia, the stronghold of John of Giscala. Now this wall happened to stand upon that part which had been undermined by John at the time when the Romans made their former attack; and the hollow ground, weakened by the shaking caused by the battering-rams, gave way during the first night, hurling down a portion of the wall with all the sentinels upon it. The Romans, startled from their sleep by the appalling crash and by the thrilling shrieks of the doomed victims, knew not at first what had happened, but when the morning light revealed the nature of the disaster, they grasped their weapons, clambered over the ruins, and poured through the breach. But Antonia was not yet taken. John, exercising a military foresight that moved his enemies to surprise, if not to admiration, had previously raised a second wall within. As it was impossible to advance the engines through the breach, the Romans, in order to overcome this new barrier, were compelled to resort to other means. Having failed to surmount it by boldly climbing up in the very face of the enemy, they lay down at last at the foot of the wall, and, forming a testudo, or roof of shields, they sought to loosen with iron crows the lower courses of the masonry, a process attended with little hurt to the wall, but with considerable loss of life to the Romans. Now Crispus, having taken due note that a certain part of this wall declined backwards, and that the stones at this said part projected in such a manner as to afford some slight foothold, resolved to attempt a nocturnal surprise on his own account. At the dead of night he assembled fifteen of his bravest troops, including a trumpeter and an eagle-bearer.