Dessalines learned the Southern army held the Fond des Nègres plain

While Rigaud’s army was retreating into the South, in 1800, and after having seized Miragoâne, Dessalines established his headquarters on the Muzaine habitation. He fell ill there, with an illness that nearly took him to the grave. On 28 June he learned that the army of the South occupied the plain of the Fond des Nègres, that it had artillery, and that its infantry was pushing its advance posts close to Muzaine. Rigaud came from the Cayes to place himself at the head of his troops, numbering 800 men. Dessalines, informed of his plans, forestalled him. On 29 June, being gravely ill, he entrusted the command to the chief of his troops, Colonel Dommage, and he remained at Muzaine with a few regiments.

Rouzier tells this under the entry MUZAINE.