While this labour was proceeding, Alexander’s fleet was reinforced in consequence of the submission of the Cypriots and Sidonians, to an extent which enabled him to command the sea, and compelled the Tyrians to block up the mouths of their harbours. Numerous mechanics were employed in constructing military engines; some of which were placed on board the largest ships of the fleet, and the rest were mounted on the mole. The Tyrians, still to have the advantage of height, built wooden towers upon their walls facing the mole. This would seem scarcely necessary if we credit Arrian’s assertion, that the city wall in that part was 150 feet high;[15] but it gives us a scale for measuring the altitude of Alexander’s towers, which we may assume, from this precaution, to have been as great or greater. On the side to the sea they cast fiery darts into the attacking ships, and showers of stones, which not only did much harm in their fall, but raised a bank which made it impossible to get close up to the walls. The Macedonians therefore were obliged to clear away these impediments; a work in itself of difficulty and labour, increased by the resolution of the Tyrians, who openly, by sending armed ships, and secretly, by means of divers, cut adrift from their moorings the vessels employed on this service. The Macedonians frustrated this method of defence by using chains instead of cables for mooring, and succeeded at last in clearing away the bank, and getting access to the wall. On the north side, and that next the mole, it resisted their efforts; but a breach was effected on the south side by battering from the ships, and an assault was made, but without success. On the third day afterwards, the breach being enlarged, a second assault was made under Alexander in person, and the town was carried. Eight thousand Tyrians were slain, and thirty thousand persons, natives and strangers, are said to have been sold for slaves. The most remarkable feature of this siege is the battering in breach from the shipping, which would seem a most unstable base for the cumbrous and weighty engines which must have been used. It may be wished that Arrian had been more explicit on this subject, but he has given no explanation of the means employed. Quintus Curtius relates far greater wonders, and in the same proportion is less worthy of belief than the plain and unassuming statement of Arrian, which we have followed.