Pedro Navarro, count of Oliveto (c.1469-1528) was a highly successful Spanish engineer who entered French service after the Spanish government refused to pay his ransom after he was captured at the battle of Ravenna in 1512.
Navarro was born in the Roncal valley in around 1460. His early career is unclear, but he is known to have served under Cardinal Juan de Aragon before 1485 and then moved to Italy, where he served as a condottiere. During this period he is known to have fought against the Barbary pirates and is also said to have taken part in the 1487 siege of Sarzanello, where he witnessed the failure of an early attempt to destroy fortifications with a gunpowder mine.
In 1499 Navarro entered the service of Gonzalo de Cordoba, the 'Grand Captain'. He took part in Cordoba's attack on the Turkish fortress of Cephalonia in 1500, where he demonstrated his skills as siege engineer, using mines to breach the walls.
In 1501 France and Spain invaded the kingdom of Naples, which they had agreed to split between them (Second Italian War). The initial conquest went well, but the allies soon fell out and open war broke out between them. At first the Spanish were forced onto the defensive. While Cordoba was besieged in Barletta in Apulia (August 1502-April 1503), Navarro defended Canosa (1502) and then Taranto (1503). He rejoined the main Spanish field army when Cordoba received reinforcements and decided to go onto the offensive. He advanced to Cerignola, where Navarro built a series of field fortifications. When the French attacked the new Spanish position they suffered a heavy defeat (battle of Cerignola, 28 April 1503) and were forced to go onto the defensive while they awaited reinforcements.
This gave Navarro time to capture most of the French-held castles in the kingdom, although the fortress of Gaeta held out against him. His most dramatic success came at the castle of Uovo, where he spent three weeks digging a tunnel through the rocks under the castle. On 26 June the mine was exploded, destroying the chapel and killing the governor and his council, who were using it as a meeting room. The surviving defenders immediately surrendered.
The French were finally reinforced and a standoff developed on the Garigliano River. Once again Cordoba eventually went onto the offensive, and once again Navarro played a part in the Spanish victory (battle of the Garigliano, 28-29 December 1503). He was created Count of Oliveto for his part in this victory. After the battle Gaeta finally surrendered to the Spanish.
In 1507 Navarro returned to Spain, but a short time later he joined Cardinal Jimenes de Cisneros' expedition to North Africa, serving as the Cardinals' military commander. In 1508 he built a floating battery that helped with the capture of Veléz de la Gomera, then a rocky island off the Moroccan coast being used as a pirate base. The island remained in Spanish hands until 1522 but was recaptured again in 1564 and is still ruled by Spain.
In 1509 Navarro took part in the capture of Mazalquivir (Mers el Kebir) and Oran. In 1510 he commanded the Spanish army that captured Bougie (after a siege), Algiers and Tlemcen (both surrendered) and Tripoli (by assault). He then suffered a defeat on the island of Gelves (August 1510), which ended his conquests.
In 1511 he returned to Italy to fight in the War of the Holy League (1510-14), serving under Ramon de Cardona. Early in 1512 he took part in the failed Spanish siege of Bologna. His engineers dug a mine that reached the Castiglione Gate, but the defenders sank a shaft into his mine chamber. When the mine was exploded this shaft reduced the blast and the wall survived.
The siege was then lifted by the gifted French commander Gaston de Foix. The Spanish retreated, and Gaston advanced to besiege Ravenna. This triggered an Imperial counterattack, leading to the battle that Gaston had hoped for. Navarro provided some mobile artillery for the Imperial army by mounting light guns on carts, and also commanded the Spanish infantry during the battle of Ravenna (11 April 1512). Despite this innovation the battle ended as a major French victory, marred by the death of Gaston late in the day.
Navarro was captured during the battle. Despite his impressive record King Ferdinand of Spain refused to pay his ransom. Navarro eventually decided to join the French service, bringing not only his engineering skills, but also his contacts on the Spanish border, which allowed him to recruit troops for Francis I's first invasion of Italy. In June 1515 he helped Francis I invade Italy across the rarely used Argentière Pass. He fought at Francis's great victory of Marignano (13-14 September 1515) and then helped capture the castle of Milan.
Navarro was still in French service during the First Hapsburg-Valois War of 1521-26. He fought at the French defeat of La Bicocca (27 April 1522), and then retreated to Genoa, where he was captured soon afterwards. He thus missed the massive French defeat at Pavia in 1525. He was released after the Treaty of Madrid of 1526, which ended the war, but Francis renounced the treaty immediately after his release, triggering the Second Hapsburg-Valois War (1526-30).
In 1527 Marshal Odet de Foix, Count of Lautrec, led a French army into Italy. Navarro was present with this army, but was captured later in the same year and was imprisoned in the Neapolitan castle of Castel Nuovo, where he died in 1528.