The Siege of Montauban (French: Siège de Montauban) was a siege accomplished by the young French king Louis XIII from August to November 1621, against the Protestant stronghold of Montauban. This siege followed the Siege of Saint-Jean-d'Angély, in which Louis XIII had succeeded against Rohan's brother Benjamin de Rohan, duc de Soubise.Despite a strength of about 25,000 men, Louis XIII was unable to capture the city of Montauban, and he had to raise the siege and abandon after 2 months.