In November 1806, army officers and established anciens libres (pre-independence freedmen) landowners--an electorate dominated by the mulatto elite--elected a constituent assembly that was given the task of establishing a new government. Members of the assembly drafted a constitution that established a weak presidency and a comparatively strong legislature. They selected Christophe as president and Pétion as head of the legislature, the earliest attempt in Haiti to establish what would later be known as the politique de doublure (politics by understudies). Under this system, a black leader served as figurehead for mulatto elitist rule.

The only defect in the mulattoes' scheme was Christophe himself, who refused to be content with his figurehead role. He mustered his forces and marched on Port-au-Prince. His assault on the city failed, however, mainly because Pétion had artillery and Christophe did not. Indignant, but not defeated, Christophe retreated to north of the Artibonite River and established his own dominion, which he ruled from Cap Haïtien (which he would later rechristen Cap Henry). Periodic and ineffectual clashes went on for years between this northern territory and Pétion's republic, which encompassed most of the southern half of the country and boasted Port-au-Prince as its capital.

The northern dominion became a kingdom in 1811, when Christophe crowned himself King Henry I of Haiti.