マインツ大司教
In 1797, Prince Henry Louis of Nassau-Saarbrücken died childless and Charles William inherited his principality. However, under the Treaty of Lunéville, the territories on the left bank of the Rhine were lost to France. The Reichsdeputationshauptschluss of 1803 compensated Charles William with territories taken from the Electorate of Mainz, the Electorate of Cologne, Electorate of the Palatinate and Hesse.