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.
Important towns beside Cottbus and the historic capitals Lübben and Luckau include Calau, Doberlug-Kirchhain, Finsterwalde, Forst, Guben/Gubin, Lauchhammer, Lübbenau, Senftenberg, Spremberg, Vetschau, and Żary in present-day Poland.