Alexander had strong reasons for wishing to subdue Tyre. He could not invade Egypt with safety whilst the Persians were masters of the sea; and he could not think of leaving behind a large extent of country, whose inhabitants were but doubtful friends. He likewise was apprehensive of commotions and intrigues at home whilst he was pursuing Darius. The conquest of Tyre would make the whole of Phœnicia safe, would dispossess Persia of half its navy, and would lay open to him the isle of Cyprus and all Egypt. It was impossible to approach the city near enough to storm it, without making a causeway from the mainland to the island, and this seemed to be attended with insurmountable difficulties. The little arm of the sea was exposed to the west winds, which sometimes raised such storms as must sweep away any works of art. Besides, the city being surrounded by the waves, and the wall projecting into the sea at the lower part, scaling-ladders or batteries could only be fixed in the ships; and the machines could not be expected to do much execution from unsteady galleys upon tumultuous waves. Obstacles, however, only increased the determination of Alexander. But as his ships were few and at a distance, he at first attempted to come to an accommodation. He sent heralds to propose a peace; but these the Tyrians killed, contrary to the laws of nations, and threw them from the top of the walls into the sea. Alexander, highly exasperated, immediately set about making a dyke. He found materials in the stones and rubbish of old Tyre; and Mount Libanus, so famous for its cedars, furnished him with piles and other timbers. No general excelled Alexander in the art of urging his soldiers to any undertaking he wished to be executed, and, under his own personal supervision, the dyke advanced rapidly; the piles were driven with ease into the slime, which served as mortar to the stones, and they were too far from the city to meet with interruption. But as they advanced into deep water, the difficulties of operation became greater, and the workmen were constantly annoyed by the darts and arrows from the walls. Being masters of the sea, the Tyrians attacked the people and injured the works in boats, jeering them with crying, “See what capital beasts of burden these conquering heroes make!” and then asking “whether their master thought himself greater than Neptune; and whether he thought he could prevail over that god?”