First, a French army of 16,000 men under Henri, Prince of Condé besieged the castle held by 600 Spanish from 9 June 1639. After a siege of 40 days, the Spanish garrison surrendered on 19 July.
But 6 weeks later a large Spanish army of 24,000 men, (13.000 catalans recruited by the government of the Principality of Catalonia), under Filippo Spinola and Francesc de Tamarit appeared and now besieged the French garrison of 2,000 men. Condé sent an army of 22,000 men to lift the siege, but suffering from very bad weather, they were defeated in battle by the Spanish on 2 November, with the loss of 3,000 men. Now Salses was doomed and hunger forced the French to surrender on 6 January 1640. By then only 800 Frenchmen, of whom 300 sick, were left. The Spanish army had also lost 10,000 men to disease and desertions.