Count palatine of the Rhine

The Elector of the Palatinate (German: Kurfürst von der Pfalz) ruled the Palatinate of the Rhine in the Kingdom of Germany and the Holy Roman Empire from 915 to 1803.

The Palatinate emerged from the County Palatine of Lotharingia which came into existence in the 10th century.

During the 11th century, the Palatinate was dominated by the Ezzonian dynasty, which governed several counties on both banks of the Rhine. These territories were centered around Cologne-Bonn, but extended south to the Moselle and Nahe Rivers. The southernmost point was near Alzey.

From c.1085, after the death of the last Ezzonian count palatine, Herman II of Lotharingia, the Palatinate lost its military importance in Lotharingia. The territorial authority of the count palatine was reduced to his counties along the Rhine, henceforth called the County Palatine of the Rhine.

The first hereditary Count Palatine of the Rhine was Conrad of Hohenstaufen, who was the younger brother of Emperor Frederick Barbarossa. The territories attached to this hereditary office began with those held by the Hohenstaufens in Franconia and Rhineland. (Other branches of the Hohenstaufen dynasty received territories including lands in Swabia and Franche-Comté). Part of this land derived from their imperial ancestors, the Franconian emperors, and part from Conrad's maternal ancestors, the Saarbrücken. This explains the composition of the inheritance that comprised the Upper and Rhenish Palatinate in the following centuries.

...
Wikipedia