After the alliance formed between the Romans and Hiero king of Syracuse, and the capture of Agrigentium, they resolved to use all their efforts for the entire subjugation of Sicily. As, however, the Carthaginians were extremely powerful by sea, they could not hope to accomplish this object, unless they were able to cope with them on that element. They resolved, therefore, no longer to trust in any degree to hired vessels, but to build and equip a formidable fleet of their own. Powerfully actuated by this resolution, they began the arduous undertaking with that ardour and spirit of perseverance, which so eminently distinguished them; they deemed it absolutely necessary to have 120 ships. Trees were immediately cut down in the forests, and the timber brought to the sea shore: and the whole fleet, according to Polybius, was not only built, but perfectly equipped and ready for sea, in two months from the time the trees were felled. Of the 120 vessels of which it was composed, 100 had five benches of rowers, and 20 of them had three benches. There was, however, another difficulty to be overcome. It was absolutely necessary that the men, who were to navigate and fight these ships, should possess some knowledge of their art; but it was in vain to expect that with the Carthaginians, so powerful and watchful at sea, the Roman ships would be permitted to cruise safely long enough to make them practised sailors and fighters. To obviate this difficulty, they had recourse, according to Polybius, to a singular but tolerably effectual mode. "While some men were employed in building the galleys, others, assembling those who were to serve in the fleet, instructed them in the use of the oar after the following manner: they contrived benches on the shore in the same fashion and order as they were to be in the galleys, and placing their seamen, with their oars, in like manner on the benches, an officer, by signs with his hand, instructed them how to dip their oars all at the same time, and how to recover them out of the water. By this means they became acquainted with the management of the oar; and as soon as the vessels were built and equipped, they spent some time in practising on the water, what they had learnt ashore."