For his extensive political and military success, he was made Duke of Santángelo (1497), Terranova (1502), Andría, Montalto and Sessa (1507), and earned the nickname El Gran Capitán ("The Great Captain").

[1][3] He developed them as part of a combined arms doctrine including fields as disparate as cavalry, artillery, fortifications, guerrilla, siegecraft and diplomacy.

[2] The changes implemented by Fernández de Córdoba, which led to the formation of the tercios, were instrumental in making the Spanish army the dominant land force in Europe for over a century and a half.

[1][4][5] Córdoba rose to international prestige during his career, maintaining active relationships not only with the crowns of Castile and Aragon, but also with France, the Papal States, the Italian city-states and the Holy Roman Empire, all of which sought out his services.

[7][8] Once the Catholic Monarchs had consolidated their rule, they embarked in 1481 on a ten-year campaign to conquer Granada, the last remaining Muslim stronghold on the Iberian peninsula.

The Catholic Monarchs were anxious to reverse French success in Naples and selected Fernández de Córdoba to lead an expeditionary force against Charles.

Fearful of being trapped in Italy, Charles installed Gilbert de Bourbon as Viceroy of Naples and returned to France with about half of the French forces.

In their first major engagement on 28 June 1495, Fernández de Córdoba was defeated at the Battle of Seminara against French forces led by Bernard Stewart d'Aubigny.

The Spanish employed effective guerrilla tactics, striking quickly to disrupt French supply lines and avoiding large-scale battles.

[9] When Fernández de Córdoba returned to Spain he drew on the lessons from the Italian campaign to restructure the Spanish forces and military strategy.

To overcome this weakness, Fernández de Córdoba introduced a new infantry formation armed with pikes and a heavy, shoulder-fired gun called an arquebus.

[9] After Louis XII succeeded Charles as king of France in 1498, he quickly declared his intention to re-invade Italy and once again seize Naples.

Fernández de Córdoba returned to Italy leading a large force on the pretext of joining with France and Venice to attack the Ottomans in the Ionian Sea.

For a time Fernández de Córdoba did fight the Turks, seizing the strongly held island of Cephalonia in December 1500 after a two-month siege.

Fernández de Córdoba returned to Naples and after Frederick IV abdicated, the French and Spanish fought a guerilla war while negotiating the partition of the kingdom.

Gonzalo formed his infantry into units called coronelías with pikemen tightly packed in the center and arquebusiers and swordsmen on the flanks.

Unable to mount a defense after these losses, the French were allowed to evacuate Italy by sea and forced to sign the Treaty of Blois in 1505, relinquishing their hold on Naples.

[7][13] Although Fernández de Córdoba was awarded the additional title, Duke of Sessa, he never received the promised appointment to lead the Santiago military order.