First Genoese-Savoyard War

Relief of Genoa
Part of the Thirty Years' War
Relief of Genoa by the Marquis of Santa Cruz by Antonio de Pereda. Museo del Prado.
Date March 28 – April 24, 1625 Location Genoa, Republic of Genoa (present-day Italy) Result Decisive Spanish-Genoese victory Spanish invasion of the Piedmont France surrenders its claims on Savoy and Valtellina and withdraws its troops from the Piedmont and the Republic of Genoa, stipulated by the Treaty of Monzón Reconquest of some territories in the French Riviera by the combined forces of Spain and the Republic of Genoa
Belligerents
Kingdom of France  Duchy of Savoy	Spain  Republic of Genoa
Commanders and leaders
François de Bonne, Duke of Lesdiguières Charles Emmanuel, Duke of Savoy	Álvaro de Bazán, Marquis of Santa Cruz Gómez Suárez de Figueroa, Duke of Feria Carlo Doria, Duke of Tursi
Strength
30,000 infantry 3,000 cavalry	2,700–4,000 Spanish infantry (Genoa) 23 galleys 15,000 Spanish-Genoese (After the relief)
Casualties and losses
5,000 dead or wounded 2,000 captured	1,300 dead

Decisive Spanish-Genoese victory

The Relief of Genoa took place between 28 March 1625 and 24 April 1625, during the Thirty Years' War. It was a major naval expedition launched by Spain against the French-occupied Republic of Genoa, of which the capital Genoa was being besieged by a joint Franco-Savoyard army composed of 30,000 men and 3,000 cavalry.

In 1625, when the Republic of Genoa, traditionally an ally of Spain, was occupied by French troops of the Duke of Savoy, the city underwent a hard siege. It was known in Genoese governmental circles that one of the reasons why the Dutch government had offered their help to the Franco-Savoyan army was so that they could "hit the bank of the King of Spain".

However, the Spanish fleet commanded by General Álvaro de Bazán, Marquis of Santa Cruz, came to the aid of Genoa and relieved the city. Returning its sovereignty to the Republic of Genoa and forcing the French to raise the siege, they consequently began a combined campaign against the Franco-Savoyan forces that had overrun the Genoese Republic one year before. The joint Franco-Piedmontese army was forced to leave Liguria and Spanish troops invaded Piedmont, thereby securing the Spanish Road.Richelieu's Invasion of Genoa and the Valtelline had resulted in his humiliation by the Spaniards.

In northern Italy, Philip IV of Spain had followed his father's efforts to defend Catholics in the valleys of Valtellina against the Protestants in Graubünden. In 1622 Richelieu had arranged an anti-Spanish league with Venice and Savoy. With his ascendancy, the French policy changed.

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Wikipedia