Arms of the Duchy of Nassau
The House of Nassau is a diversified dynasty in Europe. It is named after the German lordship associated with the castle of Nassau, which is today located in the Rhineland-Palatinate. They were originally titled Count of Nassau, then elevated to the princely class as princely counts. At the end of the Holy Roman Empire, they proclaimed themselves Duke of Nassau.
Arms of the House of Nassau
The first person to be called Count of Nassau was Walram I of Nassau, who lived in the second half of the 12th century. His grandsons Walram II and Otto I split the Nassau possessions. The descendants of Walram became known as the Walram Line, which became important in the Nassau county. The descendants of Otto became known as the Otton Line, which inherited parts of the Nassau county, France and the Netherlands.
In 1783, the chiefs of various branches of the House of Nassau sealed the Nassau Family Pact (Erbverein) to regulate future succession in their states.
The House of Orange-Nassau stems from the Ottonian Line. The second person was Engelbert I, who offered his services to the Duke of Burgundy, married a Dutch noblewoman and inherited lands in the Netherlands, with the barony of Breda as the core of the Dutch possessions.
The importance of the Nassaus grew throughout the 15th and 16th century. Hendrik III of Nassau-Breda was appointed stadtholder of Holland, Zeeland and Utrecht by Charles V, Holy Roman Emperor in the beginning of the 16th century. Henry was succeeded by René of Châlon-Orange in 1538, who was, as his full name stated, Prince of Orange. When René died prematurely on the battlefield in 1544 his possessions passed to his nephew, William I of Orange. From then on the family members called themselves "Orange-Nassau." After the post-Napoleanic reorganization of Europe, the head of House of Orange-Nassau gained the title "King/Queen of the Netherlands". The branch of Nassau-Siegen was a collateral line of the House of Nassau, and ruled in Siegen. The first Count of Nassau in Siegen was Count Henry of Nassau-Siegen (d. 1343), the elder son of Count Otto I of Nassau. His son Count Otto II of Nassau ruled also in Dillenburg. In 1606 the House was separated from the House of Nassau-Dillenburg. After the main line of the House became extinct in 1734, Emperor Charles VI transferred the county to the House of Orange-Nassau. Nassau-Weilburg was a state in what currently is Germany, a state that existed from 1344 to 1816. The sovereigns of this house afterwards governed Nassau until 1866 and from 1890 the Grand Duchy of Luxembourg. The branch of Nassau-Weilburg ultimately became rulers of Luxembourg.
On July 17, 1806 the remaining Counties of Nassau-Usingen and Nassau-Weilburg joined the Confederation of the Rhine. Under pressure from Napoleon both counties merged to the Duchy of Nassau on August 30, 1806 under joint rule of Prince Frederick August of Nassau-Usingen and his younger cousin Prince Frederick William of Nassau-Weilburg. As Frederick August had no heirs he agreed that Frederick William should become sole ruler after his death. Nevertheless Frederick William died from a stair fall at Weilburg Castle on January 9, 1816 and his son William became Duke of unified Nassau.
At the 1815 Congress of Vienna the Nassau possessions had joined the German Confederation. Through the extinction of most lines, the Nassau-Usingen branch of the Nassau-Weilburg line under Duke William became the reigning house of Nassau until after the Austro-Prussian War in 1866 it was annexed by the Kingdom of Prussia and incorporated into the Province of Hesse-Nassau. William's son Adolphe, last Duke of Nassau, received Luxembourg after the male line of Nassau-Dillenburg became extinct in 1890.
As it is a large and complicated dynastic tree, it is easier to just provide a link here to a list of Nassau's various divisions and lines.
Key identification notes: Despite the bewildering array of issuing lines, nearly all can be identified at least to Nassau by the distinctive lion arms with hashed field. "NASS" or variants appear in the legends of larger coins.
Various small coins: