Pax Italiana or how a defeat of Valois in the Hundred Years War saved Catalonia
Earlier Unification of Italy
POD
Joan of Arc was defeated captured by the force of the English on Orleans and the English and Burgundian forces devastate the Orleans in 1427 thus causing it's inhabitants to submit to the Plantagenet Dynasty of France and the French military was defeated by the force of Burgundy and England, thus the Valois retreat and the Lancastrians enter France and sends a large force to destroy the French resistance completely, The Valois retrated to Provence which is under a Valois dynasty and Dauphine was incorporated to Provence while Lyonais slipped to the Burgundians, the English thought they won but whoever wins the Plantagenets or Valois they lose.
In 1440 The Valois especially Rene of Provence concentrated on their disputes with Aragon and Savoy because of their territorial claims, the Valois and Visconti plotted against Savoy, so after the plot Savoy was annexed to Milan and defeat the Trastamara on Aragon which caused the County of Barcelona, Sicily and Sardinia to fall under Valois hands, the Valois give up Sicily and Naples as a dowry of Margarita De Valois (Margaret D'Anjou in OTL) to her marriage to Francesco Sforza, who now have the most lands in Italy.
But there are still some problem duchies and the Papal state that threaten the integrity of the new state.