In 1806, with Napoleon's victory over coalition forces, the Holy Roman Empire was finally dissolved. The Landgraviate of Hesse-Darmstadt was incorporated into Napoleon's Confederation of the Rhine, a French puppet state. Not all Hessian soldiers were happy with this outcome; the Leib-Füsilier Regiment's and the Leibgarde Regiment's respective Majors took all the men they could and deserted to the Kingdom of Prussia.
They formed the 7. Fußbataillon (7th Foot Battalion), comprised of Hessians who refused to fight for the French and fought under their new Prussian banner to reclaim Hesse. As the war went on, more Hessians fled their homeland to save it, and the size of the 7. Fuß grew and grew, eventually exceeding the size of a normal battalion, and they were awarded a detachment of Jägers, a small battery, and even a squadron of cavalry.
However, they chose to keep their designation, as they had come to pride themselves in their banner and accomplishments, training their recruits to become the best, and one day return to Hesse as its liberators.