But it was Philip II who established today's concept of a landing force. This was a pure naval power projection ashore by forces deployed from ships that could maintain their ability to fight despite being based on board.
This is the period of the famous Tercios literally "One Third", due to its organisation: one third of musketeers , one third of swordsmen and the final third of pikemen : [ 2 ] [ 3 ].
Of the Tercios above, the first is considered the core of the Spanish Marine Infantry, and it bears in its coat of arms two crossed anchors that became the Corps' coat of arms until In , the Cuerpo de Batallones de Marina was definitively settled and organized into a battalion corps with a corresponding regimental HQ overseeing the supervision of these units. Their mission was to form the "Main body of landing columns and ship's soldiers tasks" in a time that boarding was still a critical part of battle at sea.
They were also gun crews. In a marine artillery corps was founded. At mid 18th century there were 12, marine infantry and 3, marine gunners.
The infantry formed boarding parties while the gunners manned the ship cannons. As needed landing parties were formed. Both corps also garrisoned the navy's coastal fortresses. During the War of Spanish Independence both the marine infantry and the marine artillery was reorganized as an administrative division of seven regiments, mainly fighting on land as part of army divisions in an operational role.
