On his father's death in 1571, the young Alfonso Félix succeeded as 3rd
Prince of Francavilla, 3rd
Prince of Montesarchio, 4th
Marquess of Vasto, 8th
Marquess of Pescara, and
Count of Monteodorisio, and a
Grandee of Spain. He was appointed as Cavalry officer under the orders of
Alexander Farnese, Duke of Parma for Spain during the
Dutch Revolt (part of the
Eighty Years' War). In 1584, he received the order to leave for
Flanders, while his pregnant wife returned to Pesaro. Between July and August 1585 Alfonso Félix took part in the
Siege of Antwerp. After returning home briefly, he went back to Flanders at the end of April 1586 where he fought, and won, the
Battle of Zutphen in September 1586. At the end of November 1586, he was promoted by Alessandro Farnese, on the orders of King
Philip II, in light of his success in Flanders, with the position of General of the Light Cavalry of Flanders, also receiving the collar of the
Order of the Golden Fleece. While preparing for the Army's expedition against the
Kingdom of England, the position of General of Cavalry became vacant (due to the death of the previous holder,
Robert de Melun, Viscount of Gent and Marquess of Roubaix). Alfonso Félix and Walloon
Emmanuel de Lalaing, Marquess of Renty were the two candidates, however, Alfonso Félix was selected for political reasons and he accepted, providing his consent to the Sovereign's adviser
Juan de Idiáquez y Olazábal. Alfonso Félix, quite ill, returned to Italy in 1589. In 1592, the Duke of Parma went to the baths of
Spa, hoping to obtain help for his ailments, together with a retinue that included among others, Alfonso Félix, the
Prince of Ascoli, and
Don Rodrigo Niño
Laso de la Vega. Alfonso Félix's health conditions worsened over the course of the year with recurrent bouts of dizziness and paralysis. Also in 1592, he was involved as a witness, in a matter of honor between his first cousin, the
Duke of Mantua, and the Duke of Parma. The matter required the intervention of the Pope and the King of Spain, who commissioned Alfonso Félix's brother-in-law, the
Duke of Urbino, to act as peacemaker. Alfonso Félix's wife Lavinia herself intervened personally in settling the dispute. In 1593, Alfonso Félix was appointed General of the Cavalry of the
Duchy of Milan, replacing
Don , along with Lieutenant
Alonso de Guzmán y Sotomayor, 7th Duke of Medina Sidonia. However, due to his health problems, he left the Army to go the thermal baths at
Procida and
Ischia. In November 1593, he traveled to
Rome to support the appointment to
Cardinalate of his brother
Tomás where he died of a stroke on 2 December 1593. ==Personal life==