Dessalines and Pétion advanced in two columns on Mirebalais.

Dessalines sets out at last from La Petite-Rivière with the 4th, 7th, 10th and 12th demi-brigades, while Pétion leaves Arcahaye with the 3rd and 8th. The first, forming the left column, debouches on 7 prairial (27 May) upon Le Mirebalais by the road of Selle; the second, forming the right column, advances by the road of Madame-Michel. David-Troy warns of this irruption the General Kerverseau, then at Las-Cahobas; he himself evacuates the town of Saint-Louis and withdraws upon the redoubts that command it, whose fortifications he had caused to be increased. Kerverseau moves upon the Lafond plantation in the plain of Le Mirebalais, at the head of 300 men of the 89th and of the national guard of Las-Cahobas, plus 70 cavalrymen under the orders of Ailhaud, military commandant of Bani (1), with the intention of going to relieve David-Troy. “The enterprise was bold,” says Kerverseau (2), “but Le Mirebalais had to be saved at any price; I was convinced besides that a stroke of audacity would astonish the enemy and that the dangers of flight would force the Spaniards to fight.”