Marines, also known as a marine corps or naval infantry, are typically 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 an integral part of the navy, but it can also be under the army like the Troupes de marine and Givati Brigade, or form an independent service branch like the United States Marine Corps and the Royal Marines.
Historically, tasks undertaken by marines have included: helping maintain discipline and order aboard the ship, 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.