In 1813, Yermolov fought at Lützen, where he was accused of insubordination and transferred to command the 2nd Guard Division.
He joined the retreat from Russia, and later distinguished himself at the battles of Lutzen, Bautzen, Dennewitz, Hanau, and Hochheim in the War of the Sixth Coalition as the Allies defeated Napoleon.
According to the will of John George I, Christian received Merseburg and the cities of Bad Lauchstädt, Schkeuditz, Lützen, and Zwenkauand with their castles, half of the towns of Brehna, Zörbig, and Finsterwalde, and the Margraviate of Lower Lusatia, including the towns and castles of Lübben, Dobrilugk, Finsterwalde, Guben, Luckau, Calau, and Spremberg; this settlement created the Duchy of Saxe-Merseburg with Christian as its ruler.
He left Paris and was a captain in the 1813 Saxony campaign, assisting at the battles of Lützen and Bautzen (at the latter he was decorated personally by Napoleon).
Brahe took part in the long duel between Gustavus and Wallenstein around Nuremberg as general of infantry, and commanded the left wing at Lützen on November 6, 1632, where he was the only Swedish general officer present.