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Tercio

Tercio is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tercio rather than just read about it. In short: 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.

Tercio — main illustration
Tercio — illustration

Key takeaways

  • Tercio belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Tercio to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Tercio from memory before moving on to harder problems.

Reference excerpt

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 created to fight colonial wars in North Africa, similar to the French Foreign Legion. These formations were actually regiments bearing the name of tercio as an honorary title.

History

During the Granada War (1482–1491), the soldiers of the Catholic Monarchs of Spain were divided into three classes: pikemen (modelled after the Swiss), swordsmen with shields, and crossbowmen supplemented with an early firearm, the arquebus. As shields disappeared and firearms replaced crossbows, Spain won victory after victory in Italy against powerful French armies, starting under the leadership of Gonzalo Fernández de Córdoba (1453–1515), nicknamed El Gran Capitán (The Great Captain). The military organizational and tactical changes made by Córdoba to the armies of Spanish monarchs are seen as the precursors of the tercios and their methods of warfare. The combat effectiveness of the Spanish pike and shot armies pioneered by Córdoba was based on an armament system that effectively united the pike with the compact firepower of the arquebus. An advantage of the Spanish pike and shot formation over its inspiration, the Swiss compact frame, was its ability to divide into mobile units and even individual melee units without the loss of cohesion. Initially, the term tercio denoted not a combat unit, but an administrative unit under a general staff, commanding garrisons throughout Italy for battles on various distant fronts. This peculiar character was maintained when it mobilized to fight the Protestant rebels in Flanders. Command of a tercio and its companies of soldiers was granted directly by the king, and companies could easily be added or removed and moved between tercios. By the middle of the 17th century, the tercios began to be raised by nobles at their own expense, patrons who appointed the captains and were effective owners of the units, as in other contemporaneous European armies. From the conquest of Granada in 1492 to the campaigns of El Gran Capitán in the kingdom of Naples in 1495, three ordinances laid the foundations of Spanish military administration. In 1503, the Great Ordinance reflected the adoption of the long pike and the distribution of infantry in specialized companies. In 1534, the first official tercio was created, that of Lombardy, and a year later it helped in the conquest of the Duchy of Milan. The tercios of Naples and Sicily were created in 1536, thanks to the Genoa ordinance of Charles V. At the Battle of Mühlberg in 1547, the imperial troops of Charles V defeated a league of Protestant princes in Germany, thanks mainly to the action of the Spanish tercios. In 1557, the Spanish army completely defeated the French at the Battle of San Quentin, and again in 1558 at Gravelines, which led to a peace greatly favoring Spain. In all these battles, the effectiveness of the tercio units stood out. The origin of the term tercio is doubtful. Some historians believe the name was inspired by the tercía, a Roman Legion of Hispania. Some think that it designated the threefold division of the Spanish forces in Italy. Others trace it to the three types of combatants (pikemen, harquebusiers, musketeers). According to an ordinance for "people of war" of 1497, where the formation of the infantry is changed into three parts.

The pawns [the infantry] were divided into three parts. The one tercio with spears, as the Germans brought them, which they called pikes; and the other had the name of shields [people of swords]; and the other, of crossbowmen and spit bearers. [later replaced by arquebusiers]. Yet others derive the name from the three thousand men mustered in the first units. This last explanation is supported by the field master Sancho de Londoño in a report to the Duke of Alba in the 16th century:

The tercios, although they were instituted in imitation of the [Roman] legions, in few things can be compared to them, that the number is half, and although formerly there were three thousand soldiers, for which they were called tercios and not legions, already it is said like this even if they do not have more than a thousand men.

Composition and characteristics

… excerpt ends here. Continue reading the full article.

Illustrations

Tercio illustration
Tercio: 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.
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.
Tercio: Tercios disembarking, 1583
Tercios disembarking, 1583
Tercio: A bastioned square in battle
A bastioned square in battle
Tercio: Organization of a tercio
Organization of a tercio

Worked examples

Example 1 — a first encounter with Tercio

Start with the simplest possible case. Write down what Tercio claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tercio before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tercio ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tercio

In research
Tercio appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Tercio in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Tercio is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1534 establishments in the Spanish Empire, House of Habsburg, Infantry units and formations, so understanding it makes those chapters shorter.
In everyday life
Look for Tercio outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tercio in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Tercio means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Tercio out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tercio in simple terms?

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 po…

Why does Tercio matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tercio?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tercio.

Tags

  • 1534 establishments in the Spanish Empire
  • House of Habsburg
  • Infantry units and formations
  • Military strategy
  • Military tactics
  • Military units and formations of Spain
  • Military units and formations of the Italian Wars
  • Military units and formations of the early modern period
  • Spanish inventions

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