Don Pedro Navarro, Count of Oliveto, was probably born at Garde in the Navarrese valley of Roncal.

Little is known of his early life.

He began his military career in the service of Cardinal Juan de Aragon prior to 1485.

He fought against the Barbary pirates in Italy as a condottiere.

Enlisted by Gonzalo Fernández de Córdoba in 1499, he took part in the capture and siege of Cephalonia in 1500.

His skillful employment of mines had allowed for the breaching of the walls of the Turkish fortress.

He had continued in the service of Gonzalo Fernández de Córdoba and gone on to Naples, and defended Canosa in 1502 and Taranto in 1503 against the French.

His supervision of the construction of the field fortifications at the Battle of Cerignola had enabled Gonzalo Fernández de Córdoba to win his battle with Louis d'Armagnac, Duke of Nemours on April 28.

He played a major role in the Spanish victory at the Garigliano River on December 29, 1503 and had been created count of Oliveto for his services.

After returning to Spain in 1507, he takes part in Cisneros’ expeditions to North Africa.

In 1508, Navarro assists in the capture of Peñón de Vélez de la Gomera, a natural island in the Alboran Sea, by employing a floating battery of his own design during the battle.