The Roman Navy (Classis) was the naval forces of the Roman state. Although the navy was instrumental in the Roman conquest of the Mediterranean basin, it never enjoyed the prestige of the Roman legions. Unlike modern naval forces, the Roman navy even at its height never existed as an autonomous service, but operated as an adjunct to the Roman army. Founded around 311 BC, the Roman navy was originally insignificant. It took the Carthaginian war to drive Rome to expand it’s navy. During the course of the First Punic War the Roman navy was massively expanded. The Roman fleets were again prominent in the 1st century BC in the wars against the pirates and in the civil wars that brought down the Republic. The great naval Battle of Actium ended the civil wars culminating in the final victory of Augustus and the establishment of the Roman Empire. During the Imperial period, the Mediterranean became a peaceful "Roman lake"; in the absence of a maritime enemy, the navy was reduced mostly to patrol and transport duties. On the fringes of the Empire in new conquests or in defense against barbarian invasions, the Roman fleets were still engaged in warfare. The decline of the Empire in the 3rd century took a heavy toll on the navy, which was reduced to a shadow of its former self, both in size and in combat ability. By the early 5th century the remaining Roman fleets were incapable of offering any resistance to the barbarian invasions.
A typical Roman war ship of the first Century B.C. the Bireme or Liburnia was driven by two rows of oars. Out riggers stabilized the ship and the whales protected the hull from ramming by enemy ships. While fast under oar, this type of vessel capsized easily under too much sail. This ship was built with plank on bulkhead construction. The crew of a Liburnia consisted of about 50-80 oar-men (Remiges) and a unit of about 30-50 marines, depending on the size of the ship. Liburnias were used everywhere in the Roman Empire, on the Nile, Rhine and Danube rivers. Compared to the fighting value of the earliest warships with only one row of oar men, the Liburnia was a more powerful ship especially when ramming an enemy ship. With a closed deck it could take more marines as any other ship this size for the purpose of hand to hand combat helping insure a victory when fighting at close quarters with a ship of the same size.