Naval infantry

Marines, also known as a marine corps or naval infantry, are an infantry force that specializes in the support of naval and army operations at sea and on land, as well as the execution of their own operations. In the majority of countries, the marine force is part of the navy, but it can also be under the army like the Troupes de marine (French Marines) and Givati Brigade (Israeli Marines), or form an independent armed service branch like the United States Marine Corps (although the United States Marine Corps is under the United States Department of the Navy).

Historically, tasks undertaken by marines have included: helping maintain discipline and order aboard the ship (reflecting the pressed nature of the ships' company and the risk of mutiny), the boarding of vessels during combat or capture of prize ships, and providing manpower for raiding ashore in support of the naval objectives.

With the industrialization of warfare in the 20th century the scale of landing operations increased; this brought with it an increased likelihood of opposition and a need for co-ordination of various military elements. Marine forces evolved to specialize in the skills and capabilities required for amphibious warfare.

In the earliest day of naval warfare, there was little distinction between sailors and soldiers on a warship. In ancient China, the first well-known naval battles took place during the Warring States period (481–221 BC), where kings ruling regional states battled against one another. Chinese naval warfare in this ancient period featured grapple-and-hook, as well as ramming tactics with ships called "stomach strikers" and "colliding swoopers". It was written in the subsequent Han dynasty that the Warring States Era Chinese had employed ge chuan ships (dagger-axe ships, or halberd ships), thought to have been a simple description of a ship manned by marines carrying dagger-axe halberds as personal weapons to defend their ship. In the west the oarsmen of Ancient Greek and Roman ships had to be capable of fighting the rowers of opposing ships hand-to-hand; though hoplites began appearing on Greek ships specifically for the boarding of enemy ships. The Roman Navy's two fleet legions, I Adiutrix and II Adiutrix, were among the first distinct naval infantry units.

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