| Conventional Long Name: | Duchy of Palatinate-Neuburg |
| Common Name: | Palatinate-Neuburg |
| Era: | Middle Ages |
| Status: | Vassal |
| Empire: | Holy Roman Empire |
| Government Type: | Principality |
| Year Start: | 1505 |
| Year End: | 1808 |
| Event Start: | Established |
| Date Start: | 30 July |
| Event1: | In personal union with the Electorate of the Palatinate |
| Date Event1: | 1556–1557 |
| Event2: | Ceded to Zweibrücken |
| Date Event2: | 1557 |
| Event3: | Sulzbach separated |
| Date Event3: | 1614 |
| Event4: | Merged with the Electorate of the Palatinate |
| Date Event4: | 1685 |
| P1: | Bavaria-Landshut |
| Flag P1: | Banner of Bavaria-Landshut.svg |
| S1: | Electoral Palatinate |
| Flag S1: | Banner of the Palatinate.svg |
| Image Map Caption: | Neuburg Castle |
| Capital: | Neuburg an der Donau |
| Common Languages: | Austro-Bavarian |
| Religion: | Counts Palatine were Roman Catholic until 1541, then Lutheran until 1614, then again Roman Catholic since 1614. |
| Title Leader: | Count Palatine |
| Leader1: | Otto Henry |
| Year Leader1: | 1505–57 |
| Leader2: | Wolfgang |
| Year Leader2: | 1557–69 |
| Leader3: | Philip William |
| Year Leader3: | 1653–90 |
| Leader4: | Charles Theodore |
| Year Leader4: | 1742–99 |
Palatinate-Neuburg (German: Herzogtum Pfalz-Neuburg) was a territory of the Holy Roman Empire, founded in 1505 by a branch of the House of Wittelsbach. Its capital was Neuburg an der Donau. Its area was about 2,750 km2, with a population of some 100,000.
The Duchy of Palatinate-Neuburg was created in 1505 as the result of the Landshut War of Succession and existed until 1799 or 1808. After the so-called Kölner Spruch (Verdict of Cologne) the duchy was created from the territories north of the Danube for Otto Henry and Philipp, the sons of Ruprecht of the Palatinate. While they were minors, their grandfather Philip, Elector Palatine, ruled the duchy until his death in 1508, followed by Elector Frederick II. In 1541, Count Palatine Otto Henry converted to Lutheranism and his palace chapel at Neuburg Castle was the first newly built Protestant church of all, consecrated on 25 April 1543 by the reformed theologian Andreas Osiander.
In 1556, Otto Henry became the Elector Palatine and the next year ceded his duchy (the so-called Young Palatinate) to Wolfgang, Count Palatine of Zweibrücken. The eldest son of Wolfgang, Philipp Louis, founded in 1569 the elder line of Palatine Zweibrücken-Neuburg, from which the Palatine Sulzbach lineage was separated in 1614.
Palatinate-Neuburg joined the Protestant Union in 1608. In 1609, the United Duchies of Julich-Cleves-Berg were in dispute following the death of the childless John William. Count Palatine Wolfgang Wilhelm claimed the territory and fought in the War of the Julich Succession, converting to Catholicism midway through in order to secure alliances. As a result, Palatine-Neuburg and the Duchies of Julich and Berg would be held in personal union. This was formalized in the Treaty of Xanten.
In 1800, the duchy was invaded by France and on June 26, 1800, the Habsburg, Württemberg and Bavarian armies fought a battle there. After fighting for most of a day, the Coalition armies withdrew. Neuburg was occupied by the French, and General Ney established his headquarters in the castle there.[1]
The Duchy of Palatinate-Neuburg was abolished in 1808. In the partition of Bavaria in 1837, Palatinate-Neuburg was joined with Swabia but became a part of Upper Bavaria in the 1970s.
With the death of Elector Charles Philip in 1742 all his territories including the state of Palatinate-Neuburg passed to the Palatinate-Sulzbach line of the Wittelsbach dynasty. Charles Theodor of the Sulzbach line was a descendant of Augustus, Count Palatine of Sulzbach, a brother of Wolfgang Wilhelm.