Gaspar de Guzmán, Count-Duke of Olivares, the chief minister of Philip IV, had been trying to distribute more evenly the huge economic and military burden of the Spanish Empire.

But his Union of Arms (Spanish: Unión de Armas) policy raised hostilities and protests all across the states of the Monarchy of Spain.

Catalan peasants, who were forced to quarter the royal army and reported events such as religious sacrileges,[1] destruction of personal properties and rape of women by the soldiers, responded in a series of local rebellions against their presence.

As a result of the negotiation, on 16 January, Pau Claris presented a proposal before the Junta de Braços by which the King of France agreed to put the Principality under his protection if Catalonia changed its government to a republic.

[9] His successor, Josep Soler, prepared the formal agreement of personal union between Catalonia and France, which was ratified by the Treaty of Peronne on 19 September 1641.

After the military success, the Junta de Braços was able to establish its own Judiciary throughout Catalan territory with the help of French armies, despite the persistence of some class war in the form of local uprisings of peasants.

Meanwhile, increasing French control of political and administrative affairs despite the agreements reached in Peronne (maritime ports, taxes, key bureaucratic positions, etc.)

and a firm military focus on the neighbouring Spanish kingdoms of Valencia and Aragon, in line with Richelieu's war against Spain, gradually undermined Catalan enthusiasm for the French.

A Franco-Catalan army under Philippe de La Mothe-Houdancourt moved south and gained several victories against the Spanish, but the sieges of Tarragona (1644), Lleida and Tortosa finally failed and the allies had to withdraw.

Then, the French armies and officers, as well as Catalans loyal to them, retreated to the northern side of the Pyrenees, retaining control of the Roussillon while maintaining the claim over the entirety of Catalonia.

Resistance continued for several years afterwards and some fighting took place north of the Pyrenees but the mountains would remain from then on the effective border between Spanish and French territories.