His minority led to a power struggle between his mother, Anne of Austria, supported by Cardinal Mazarin, and his uncle, Gaston, duc d'Orléans.

[7] Faced by this double threat, Francisco de Melo, Governor of the Spanish Netherlands, prioritised retaining the northern Flemish ports of Ghent and Antwerp; Gravelines could not expect to be relieved.

Nominally commanded by Orléans, operations were conducted by La Meilleraye, the Master of Artillery, and de Gassion, D'Enghien's deputy at Rocroi.

With no hope of relief, and having held up the main French army for two months, the Spanish garrison 'beat the chamade' on 28 July, and received safe passage to Dunkirk.

[10] In September, the Dutch captured Sas van Gent, but doing so absorbed the entire campaigning season; this was a reasonable exchange for the Spanish, who recaptured Gravelines in 1652.

The failure to gain a decisive victory was in part due to competing objectives in the Spanish Netherlands, where the French wanted their own ports to control their trade.

[11] In 1645, the French besieged Bruges, a town allocated to the Dutch in the 1635 treaty; in 1646, a combined attack on Antwerp was cancelled after news of a proposed marriage contract between seven year old Louis XIV and Maria Theresa of Spain.