Marines are soldiers trained to operate on and deploy from warships. In the earliest days of naval warfare there was little distinction between land and sea-based soldiers. Ancient warships would temporarily draft land-based archers and spearmen onto ships to use in combat for a particular battle or campaign. It was the Romans that first raised a body of troops specifically trained and equipped to fight at sea, with two fleet legions dedicated for this purpose. These were the first true marines.
After the fall of the Roman empire, it was not until the 16th century that the idea of soldiers dedicated to serving on ships re-emerged. In the Mediterranean naval warfare was dominated by oared galleys armed with a combination of a ram and a few heavy cannons. Sea battles frequently ended with ships boarding each other. This in turn generated the need for a small body of men allocated to each galley to lead or defend against such attacks. The first organized marine corps was Venice’s Fanti da Mar (Sea Infantry) regiment. This initiative was later copied by the Spanish with their Compañías Viejas del Mar in 1537, progenitors of the current Spanish Navy Marines.
In Britain the late 17th century was a period of rapid naval reform under the newly restored Stuart kings. What emerged from this process was the modernised Royal Navy that proved so effective in the 18th century. One initiative was to recruit a dedicated force of soldiers to serve onboard ships. In 1664 the Duke of York and Albany’s Maritime Regiment of Foot was formed. In 1755 this regiment was expanded into His Majesty's Marine Forces composed of fifty Companies in three divisions, headquartered at Chatham, Portsmouth, and Plymouth. They continued to be known as marines until 1802, when they became the Royal Marines.
Marines formed a significant proportion of a warship’s crew. A British seventy-four, for example, carried a detachment of just under 100 marines as part of its compliment of 650 crew, and this significantly enhanced its fighting power. In action marines provided sharpshooters stationed in the rigging from where they could fire down on the deck of an enemy, targeting key personnel like officers and helmsmen. They also supplied a trained force to lead or resist any boarding action, just like their Roman predecessors.
When not in action, marines supplied a disciplined reserve to support the officers of a ship. They acted as sentries and had a policing role at times of tension between officers and crew. They were deliberately kept apart from sailors, were dissuaded from fraternising with them, and changed ship frequently. Marines were all volunteers, unlike many of the sailors, and messed separately from them. They slept at the aft-end of the lower deck, deliberately positioned between the crew and the officers’ accommodation. The consequences of not posting marines to a warship was shown when HMS Bounty set out on her expedition to the South Sea. With no marines to call on, Captain Bligh was left powerless when his senior officer led a mutiny against him.
Marines were also used to raid an enemy coastline. All 18th century warships carried boats which could land them. Captain Lord Thomas Cochrane used marines allocated to his frigate HMS Imperieuse to considerable effect. In a seven-month cruise off the Spanish coast in 1808 he attacked and destroyed nine shore batteries, burnt down six signal posts, destroyed several bridges, and helped a party of guerrillas capture the Castle of Mongat in a combined assault. On occasion marines were used to hold a strategic location, sometimes for several years. When the Danish island of Anholt was seized by marines from the Royal Navy’s Baltic Fleet in 1807 it was occupied by them until 1812, despite repeated attempts by the Danish army to recapture it.
In the 19th century improvements in naval gunnery increased the distance at which ships fought each other far beyond small arms range, which robbed marines of their traditional role in combat as sharpshooters or in boarding. Instead, they were allocated some guns to serve in combat, traditionally those mounted nearest the stern. However, it was their role in landing onshore that became increasingly important. This ability to project military power from the sea onto land has now come to dominate the role of the modern marine. The high point in this trend came during the Second World War in the Pacific. Allied progress from island to island was spearheaded by a massively expanded US Marine Corp acting in concert with the US Navy. By the end of the war America had almost half a million marines under arms, organised into a force with its own armour, artillery and even aircraft. To this day the US Marine Corp is by far the most powerful marine force in the world.