Tercio

A tercio (pronounced [ˈteɾθjo], Spanish for '[a] third') was a military administrative 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 essential pieces of the powerful land forces of the Spanish Empire, sometimes also fighting along with the navy. These forces were among the most dominant in the European battlefields for more than a century and a half. The Spanish tercios were some of the finest and most influential professional infantry forces in the world due to the effectiveness of their battlefield formations, and were the crucial step in the formation of modern European armies, made up of professional volunteers, instead of levies raised for a campaign or hired mercenaries typically used by other European countries of the time. The internal administrative organization of the tercios and their battlefield formations and tactics grew out of the innovations of Gonzalo Fernández de Córdoba during the conquest of Granada and the Italian Wars in the 1490s and 1500s, being among the first to effectively mix pikes and firearms (arquebuses). The tercios marked a rebirth of the use of infantry forces comparable to the Macedonian phalanxes and the Roman legions. Such formations distinguished themselves in famous battles such as the Battle of Bicocca (1522) and the Battle of Pavia (1525). Following their formal establishment in 1534, the reputation of the tercio was built upon their effective training and high proportion of "old soldiers" (veteranos), in conjunction with the particular elan imparted by the lower nobility who commanded them. The tercios were finally replaced by regiments in the early eighteenth century. From 1920, the name of tercio was given to the formations of the newly-created Spanish Legion, professional units then...