High Quality Content by WIKIPEDIA articles! From the 4th century BC on, new types of oared warships appeared in the Mediterranean Sea, superseding the trireme and transforming naval warfare. Ships became increasingly bigger and heavier, including some of the largest wooden ships ever constructed. These developments were spearheaded in the Hellenistic East, but also to a large extent shared by the naval powers of the Western Mediterranean, more specifically Carthage and the Roman Republic. While the wealthy Successor kingdoms in the East built huge warships ("polyremes"), Carthage and Rome, in the intense naval antagonism during the Punic Wars, relied mostly on medium-sized vessels. At the same time, smaller naval powers employed an array of small and fast craft, which were also used by the ubiquitous pirates. Following the establishment of complete Roman hegemony in the Mediterranean after the battle of Actium, the nascent Roman Empire faced no major naval threats. In the 1st century AD, the larger warships were retained only as flagships, and were gradually supplanted by the light liburnians until, by Late Antiquity, the knowledge of their construction had been lost.