Tercio The Tercio ( " third " ) or Tercio Español ( The Spanish Third ) was a Spanish military unit of the Spanish Empire during the era of the dominance of Habsburg Spain in Europe and the Renaissance era ] ] . [ [ File : Cross of Burgundy ( Template ) . svg | 150px | thumb | right | [ [ Cross of Burgundy was adopted as the symbol of the Tercios and the Spanish Empire ] ] The tercio was an [ [ infantry ] ] formation made up of [ [ pike ( weapon ) | pikemen ] ] , [ [ swordsmen ] ] and [ [ arquebus ] ] iers or [ [ musketeer ] ] s in a mutually supportive formation , that in theory was up to 3 , 000 soldiers , although it was usually less than half this size . It was also sometimes referred to as the Spanish Square in other countries and the formation was also much used by other powers , especially the [ [ Imperial Army of the Holy Roman Empire | Imperial Army ] ] of the [ [ Holy Roman Empire ] ] . Spanish tercios were the first modern European army , understood as an army of professional volunteers , instead of paddles for a campaign and hiring mercenaries typically used in other European countries . The formation dominated European battlefields in the sixteenth century and the first half of the seventeenth century and is seen by historians as a major development of Early Modern combined arms warfare . The Tercios were the main troops of kings as [ [ Charles V , Holy Roman Emperor ] ] and other reigns in Habsburg Spain . History . The tercio was the product of the [ [ Italian Wars ] ] , in which the Spanish general , [ [ Gonzalo Fernández de Córdoba ] ] , reorganized the [ [ Spanish army ] ] throughout a series of conflicts at the end of the 15th century and early 16th century , into a tactically unique combination of combined arms centered around [ [ Heavy infantry | armored infantry ] ] . To counter the [ [ Gendarme ( historical ) | French heavy cavalry ] ] a unit called a " colunella " ( " colonelcy " ) , commanded by a " colonel " , was created . A colonelcy could theoretically have up to 6 , 000 men but by 1534 this had been reduced to the tercio with a maximum of 3 , 000 , for increased mobility on the offense . Armies using tercios generally intended to field them in brigades of at least three , with one tercio in the front and two behind , the rearward formations [ [ echelon formation | echeloned ] ] off on either side so that all three resembled a stepped pyramid , hence the name " tercio " , which means " one third " ( that is , one third of the whole brigade or battle group ) . Composition and characteristics . [ [ File : Tercio . jpg | thumb | 400px | A " tercio " in " bastioned square , " in battle . ] ] Although other powers adopted the tercio formation , their armies fell short of the fearsome reputation of the Spanish , who possessed a core of professional soldiers , which gave them an edge that was hard for other states to match . That army was further supplemented by " an army of different nations " , a reference to the fact that many of the troops were mercenaries from Germany ( [ [ Landsknecht ] ] ) , and the Italian and [ [ Wallonia | Walloon ] ] territories of the [ [ Spanish Netherlands ] ] , as was characteristic of European warfare before the levies of the [ [ Napoleonic Wars ] ] . In the 16th and 17th centuries however , the core of Spanish armies were formed by Spanish subjects , who were frequently praised by others for their cohesiveness , superiority in discipline and overall professionalism . Formations . [ [ File : 1650 - tercio . jpg | 300px | thumb | right | Officers of a tercio : an alabardero , alférez and arcabucero . ] ] Within the " tercio " , ranks of pikemen arrayed themselves together into a hollow square ( " cuadro " ) [ [ pike square ] ] with swordsmen — typically equipped with a short sword , a buckler , and javelins — inside ; as the firearm rose in prominence , the swordsmen declined and were phased out . The arquebusiers ( later , musketeers ) were usually split up in several mobile groups called sleeves ( " mangas " ) and deployed relative to the " cuadro " , typically with one " manga " at each corner . By virtue of this combined - arms approach , the formation simultaneously enjoyed the staying power of its pike - armed infantry , the ranged firepower of its arquebusiers , as well as the ability to conduct assaults with sword - and - buckler men . In addition to its inherent ability to repulse cavalry and other units along its front , the long - range firepower of its arquebusiers could also be easily reorganized to the flanks , making it versatile in both offensive and defensive evolutions , as demonstrated by the success of the " tercios " at the [ [ Battle of Pavia ( 1525 ) ] ] . Groups of " tercios " were typically arrayed in dragon - toothed formation ( staggered — the leading edge of one unit level with the trailing edge of the preceding unit ; see similar [ [ hedgehog defense ] ] concept ) . This enabled [ [ Enfilade and defilade # Enfilade | enfilade ] ] lines of fire and somewhat [ [ Enfilade and defilade # Defilade | defiladed ] ] the army units themselves . Odd units alternated with even units , respectively one forward and one back , providing gaps for an unwary enemy to enter and outflank itself , where it would become subjected to the combined direct and raking [ [ cross fire ] ] from the guns of three separate " tercios " . From their inception , tercio formations were meant to co - ordinate their field operations with cavalry . " Tercios " and the Spanish Empire . " Tercios " were deployed all over Europe under the [ [ Spanish Empire | Habsburg Emperors ] ] , who were kings of both Spain and the Holy Roman Empire . They were made up of volunteers and built up around a core of professional soldiers and were highly trained . Sometimes later " tercios " did not stick to the all - volunteer model of the regular Imperial Spanish army – when the Habsburg king [ [ Philip II of Spain | Philip II ] ] found himself in need of more troops , he raised a " tercio " of Catalan criminals to fight in Flanders , a trend he continued with most Catalan criminals for the rest of his reign . A large proportion of the Spanish army ( which by the later half of the 16th century was entirely composed of " tercio " units : [ [ Tercio of Savoy ] ] , Tercio of Sicily ) was deployed in the Netherlands to quell the increasingly difficult rebellion against the Habsburgs , although ironically many units of Spanish " tercios " became part of the problem rather than the solution when the time came to pay them . With the Spanish coffers depleted by constant warfare , unpaid " tercio " units often turned mutinous – in April 1574 , just after winning a major victory , unpaid " tercios " mutinied and occupied the town of Antwerp , threatening to sack the town if their demands were not met . Bereft of troops , and thus his authority , the Spanish leader on the scene met the " tercios " ' demands . The Portuguese " terços " . [ [ File : Lagos46 kopie . jpg | thumb | 300px | Portuguese " terços " in the Battle of Alcácer Quibir ( 1578 ) . ] ] Portugal adopted the Spanish model of " tercio " in the 16th century , calling it terço . In 1578 , under the reorganization of the [ [ Portuguese Army ] ] conducted by King [ [ Sebastian of Portugal | Sebastian ] ] , four " terços " were established : the " Terço " of Lisbon , the " Terço " of [ [ Estremadura Province ( historical ) | Estremadura ] ] , the " Terço " of [ [ Alentejo ] ] , and the " Terço " of Algarve . Each had about 2 , 000 men , formed into eight companies . The infantry of the army organized for the expedition to Morocco in 1578 was made up of these four " terços " together with the " Terço " of the Adventurers ( totally made up of young nobles ) , three mercenary " terços " ( the German , the Italian , and the Castilian ) , and a unit of elite [ [ sharpshooter ] ] s of the Portuguese garrison of Tangier . This was the Portuguese force which fought the [ [ Battle of Alcácer Quibir ] ] . While [ [ Iberian Union | united ] ] with the Spanish Crown , from 1580 to 1640 , Portugal kept the organization of " terços " , although the Army had declined . Several Spanish " tercios " were sent to Portugal ; the principal of them , the Spanish infantry " Tercio " of the City of Lisbon , occupied the main fortresses of the Portuguese capital . The " Terço " of the Navy of the Crown of Portugal , the ancestor of the modern [ [ Portuguese Marines ] ] , was created in this period . After the restoration of [ [ Independence of Portugal | Portuguese sovereignty ] ] in 1640 , the Army was reorganized by King [ [ John IV of Portugal ] ] . The " terços " remained the basic units of the Portuguese infantry . Two types of " terços " were organized : the paid " terços " ( first line permanent units ) and the auxiliary " terços " ( second line militia units ) . Portugal won the [ [ Portuguese Restoration War | Restoration War ] ] with these " terços " . At the end of the 17th century , the " terços " were already organized as modern regiments . However , the first line " terços " were only transformed into regiments in 1707 , during the [ [ War of the Spanish Succession ] ] – after the Spanish " tercios " were transformed into regiments in 1704 . The second line " terços " were only transformed into militia regiments in 1796 . Some of the old " terços " are direct ancestors of modern regiments of the Portuguese Army . Obsolescence . [ [ File : Batalla de rocroi por Augusto Ferrer - Dalmau . jpg | thumb | The [ [ Battle of Rocroi ] ] ( 1643 ) marked the end of the supremacy of the Spanish Tercios , painting by [ [ Augusto Ferrer - Dalmau ] ] [ [ : es : Rocroi , el último tercio | picture ] ] . ] ] The first challenge to the dominance of the " tercios " came at the [ [ Battle of Nieuwpoort ] ] ( 1600 ) . The victor of Nieuwpoort , the Dutch stadtholder [ [ Maurice , Prince of Orange ] ] , believed he could [ [ Military Revolution # Linear tactics | improve on the " tercio " by combining its methods ] ] with the organisation of the [ [ Roman legion ] ] . These shallower linear formations brought a greater proportion of available guns to bear on the enemy simultaneously . The result was that the " tercios " at Nieuwpoort were badly damaged by the weight of Dutch firepower . Yet the Spanish army very nearly succeeded in spite of internal dissensions that had compromised its regular command . The [ [ Eighty Years ' War ] ] ( 1568 – 1648 ) in the Low Countries continued to be characterized by sieges of cities and forts , while field battles were of secondary importance . Maurice ' s reforms did not lead to a revolution in warfare , but he had created an army that could meet the " tercios " on an even basis and that pointed the way to future developments . During the [ [ Thirty Years War ] ] ( 1618 – 1648 ) " tercio " formations began to suffer some serious defeats to more linear formations led by the Swedish king – general , [ [ Gustavus Adolphus ] ] . Throughout its history the " tercio ' s " form and composition was never static as it evolved to meet the new challenges . " Tercio " formations employed by well trained troops with good cavalry support continued to win major battles , as can be seen in major battles like [ [ Battle of White Mountain | White Mountain ] ] ( 1620 ) , [ [ Battle of Fleurus ( 1622 ) | Fleurus ] ] ( 1622 ) , [ [ Siege of Breda ( 1624 ) | Breda ] ] ( 1624 ) , [ [ Battle of Nördlingen ( 1634 ) | Nördlingen ] ] ( 1634 ) , [ [ Relief of Thionville | Thionville ] ] ( 1639 ) , [ [ Battle of Honnecourt | Honnecourt ] ] ( 1641 ) and [ [ Battle of Valenciennes ( 1656 ) | Valenciennes ] ] ( 1656 ) . It was not until the [ [ Battle of Rocroi | Rocroi ] ] ( 1643 ) that the Spanish " tercio ' s " reputation for invincibility in major battles was shattered . Even then , the Rocroi defeat was precipitated by the collapse of the supporting cavalry arm rather than the failure of the " tercios " themselves , which had come close to besting the opposing infantry . " Tercios " continued to win important battles for a time after Rocroi and even after the Thirty Years War , but were already greatly modified from their older forms . By then , improvements in firearms and field artillery had given the new linear style a decided advantage . In response the later 17th century " " tercios " " had adopted so much of the linear style ' s organisation and tactics as to have little resemblance to the classic " tercios " of the previous century . In 1704 , the Spanish " tercios " were transformed into regiments . References . [ [ Category : Infantry units and formations ] ] [ [ Category : Military units and formations of the Early Modern era ] ] [ [ Category : Military units and formations of Spain ] ] [ [ Category : Military strategy ] ] [ [ Category : Military tactics ] ]