After the Congress of Vienna in 1815, some parts of it were returned to the last Duke, King Maximilian I Joseph of Bavaria,[1] who joined them with other former territories on the left bank of the Rhine to form the Rheinkreis, later the Rhenish Palatinate.

The County Palatine of Simmern-Zweibrücken had been created in 1410 for Stephen, the third surviving son of prince-elector King Rupert.

Both sons inherited the right to use these titles, which is why the two newly formed principalities of Palatine-Simmern and Palatine-Zweibrücken were usually described as Counties Palatine.

In 1459, the districts Falkenburg Castle, Guttenberg, Haßloch, Kirkel, Lambsheim, Oggersheim, Wachenheim, Wegelnburg and Zweibrücken from Palatine Simmern were added.

[1] However, Alexander declared his older brother mentally ill, locked him up and ruled the duchy alone.

[1] Alexander concluded an inheritance treaty with the new Elector Philip, which considerably improved relations between the two countries.

Alexander and Louis II introduced primogeniture, the rule that the whole of the principality would henceforth be inherited by the eldest son.

[1] During the Thirty Years' War, the duchy was occupied by imperial forces and Count Palatine John II of Zweibrücken had to flee to Metz.

[1] Because of this, exiled Polish King Stanisław Leszczyński who had been named Count Palatine of Zweibrücken as a Prince exercising the head of state's authority on behalf of Charles XII in 1714 was forced to leave a year after his death in 1719.

Gustav was the last Count Palatine of the Kleeburg line; when he died in 1731 without a male heir,[1] the duchy was seized by the Empire.

The French annexation of this territory was recognised by the Holy Roman Emperor in a secret clause of the Treaty of Campo Formio signed on 17 October 1797.

On 4 November 1797, the occupied territory was incorporated into the newly founded French département of Mont-Tonnerre, with its capital at Mainz.

Even the urban population were legally serfs until that status was repealed by John I on 21 April 1571 (although the situation in the city of Zweibrücken had already been somewhat eased by decrees from the years 1352 and 1483).

Administratively, the country was divided into eight districts: Zweibrücken, Homburg, Lichtenberg, Meisenheim, Trarbach, Kastellaun, Bergzabern and Guttenberg.

Regent at that time was Rupert, Count Palatine of Veldenz, who ruled in behalf of his nephew Wolfgang, who was still a minor.

While chancellor Ulrich Sitzinger and his 1557 extensive Church Order were influenced by Philipp Melanchthon, Wolfgang later adopted a stricter Gnesio-Lutheran policy.

In the period of the French Reunion (1680–1697), Catholic churches were again permitted and in 1697 under the Swedish administration after the Treaty of Ryswick, Lutheran congregations were re-established as well.

Priests were state officials and were regularly visited by a commission consisting of the district superintendent, the secular bailiff and a representative of the central administration in Zweibrücken.

There was no institutionalized national church council; initially, this function was exercised by the secular cabinet college, assisted by the superintendent of Zweibrücken.

The Reformation revived the ancient office of the Elder, a layman chosen by the community, who would supervise the lifestyle of the congregation, the pastor, the funds and the property of the parish.