A tercio, Spanish for "[a] third") was a military unit of the Spanish Army during the reign of the Catholic Monarchs of Spain and Habsburg Spain in the early modern period. They were the elite military units of the Spanish monarchy and the essential pieces of the powerful land forces of the Spanish Empire, sometimes also fighting with the navy.
Surrender of Breda, by Velázquez, shows Ambrosio Spinola (at right), commander of a Spanish tercio, receiving the keys to the city from a defeated Dutch general in 1625.
Tercios disembarking, 1583
Organization of a tercio
Schematic depiction of the pikemen's combat drill.
The Spanish Army is the terrestrial army of the Spanish Armed Forces responsible for land-based military operations. It is one of the oldest active armies – dating back to the late 15th century.
Spanish attack on a Flemish village
A soldier of the 31st Infantry Regiment of the Spanish Army during the Hispano-Moroccan War, by Augusto Ferrer-Dalmau
Spanish soldiers of the Blue Division during World War II, c. 1941
Troops of the Spanish Legion