of Saxony , Landgraves of Thuringia Electors of Saxony Kings of Poland and Grand Dukes of Lithuania Dukes of Saxe-Coburg Dukes of Saxe-Coburg-Saalfeld Dukes of Saxe-Coburg and Gotha Dukes of Saxe-Altenburg (first line of Altenburg) Dukes of Saxe-Gotha-Altenburg (second line of Altenburg) Dukes of Saxe-Hildburghausen , then Dukes of Saxe-Altenburg (third line of