Bouillon soon learned the hollowness of the promises of his allies. The Spaniards sent neither money nor men, while the Austrians received orders to march away from Sedan and to join the Spaniards, who were marching to the relief of Arras.

The duke, deserted by his allies, prepared to defend Sedan till the last. Fortunately for him, however, the position of the French at Arras was critical. The place was strong, two armies were marching to its relief, and it would therefore have been rash to have attempted at the same time the siege of Sedan. The king himself had joined the army advancing against Bouillon, while the cardinal remained in Paris. Many of those round the person of the king, foremost among whom was the Marquis of Cinq-Mars, his master of horse, spoke very strongly in favour of the duke, and represented that he had been driven to take up arms by the persecution of the cardinal. The king was moved by their representations, and gave a complete pardon to Bouillon, who was restored to the full possession of all his estates in France, while on his part he released the prisoners, baggage, and standards taken in the late battle.