Duke in Bavaria (German: Herzog in Bayern) was a title used among others since 1506, when primogeniture was established[citation needed], by all members of the House of Wittelsbach, with the exception of the Duke of Bavaria which began to be a unique position. So reads for instance the full title of the late 16th century's Charles I, Count Palatine of Zweibrücken-Birkenfeld and patriarch of the House of Palatinate-Birkenfeld: "Count Palatine by Rhine, Duke in Bavaria, Count to Veldenz and Sponheim". The title grew in importance as Wilhelm, Count Palatine of Zweibrücken-Birkenfeld-Gelnhausen began to use it, in the early 19th century, as his primary title – Duke Wilhelm in Bavaria. This choice has also had effect for his descendants.
Since 1799
On 16 February 1799, the head of the House of Wittelsbach Charles Theodore of Bavaria died without legitimate issue. Wittelsbach had been the ruling house of Bavaria since 1180 with the title of a Duke of Bavaria, and the higher title of an Elector of the Holy Roman Empire since 1623. As after the Landshut War of Succession primogeniture was established, there could only be one Duke of Bavaria anymore, resulting in the unprecedented decision to create a title of Duke in Bavaria for the rest of the family, which all members of the House took for themselves, even the older Palatine branch – the other major Wittelsbach possession. Reversely, all Wittelsbachs were also Counts Palatine by Rhine. After the death of Charles Theodore, who had unified Bavaria with the Palatinate and the other major possessions of Jülich and Berg in his person, two cadet branches were surviving: one headed by Maximilian I Joseph, Count Palatine of Zweibrücken, the other by William, Count Palatine of Gelnhausen, and both Zweibrücken and Gelnhausen were occupied by the French, which might explain why the custom was abandoned to name cadet branches by the title of their cadet possessions no matter how small.
They both agreed in the House Treaty of Ansbach that the Wittelsbach inheritances should be indivisible further on. Maximilian Joseph, being from the senior branch, inherited Charles Theodor's title of Elector of Bavaria, while William, his brother-in-law in addition to rather distant a relative, was compensated with the title of Duke in Bavaria. As head of a specific family branch, it is possible since to speak somewhat paradoxically of The Duke in Bavaria. When Wittelsbach became a Royal House, the Dukes in Bavaria were lifted to the dignity of a Royal Highness. Then if not earlier, the title of Duke in Bavaria came into formal disuse by the Royal branch, who were quite content to be Princes of Bavaria. It should be kept in mind that even if we commonly speak of a Royal and a Ducal branch of the House, it was clear that the Dukes as well were of royal rank, and to make things more complicated, the head of the royal branch is now again called the Duke: the Duke of Bavaria, of course. Among the notable members of the Ducal branch were Duke Max who, a talented Zither player and composer himself, ranks among the most important promoters of Bavarian folk-music; his daughters Empress Elisabeth of Austria, Queen of Hungary and Queen Maria of the Two Sicilies, his granddaughter Queen Elisabeth of Belgium; and in more recent times Sophie, Hereditary Princess of Liechtenstein.
In 1965 there were only two male members of the family, Duke Ludwig Wilhelm and his cousin Duke Luitpold; both were elderly and had no children. On 18 March 1965 Duke Ludwig Wilhelm adopted Prince Max of Bavaria, the second son of Albrecht, Duke of Bavaria and the grandson of Ludwig Wilhelm's sister Marie Gabrielle. From this point onwards Max has used the surname "Herzog in Bayern" in place of the surname "Prinz von Bayern". Max has five daughters, including the Sophie mentioned already, all of whom were born with the surname "Herzogin in Bayern".
John, Count Palatine of Gelnhausen (1698–1780), second son of John Charles, m. Sophie Charlotte of Salm-Dhaun, father of William, Duke in Bavaria.
Dukes in Bavaria
The members of the family used the title Duke or Duchess in Bavaria, with the style of Royal Highness. If we take 1799 as the beginning of somewhat a House of its own, the heads of this house were:
William (1799–1837), previously the Count Palatinate of Gelnhausen since 1789
Pius August (1837), only son of William, died seven months after his father
Louis William (1909–1968), first son of Charles Theodore
Luitpold Emanuel (died 16 January 1973), grandson of Max Joseph, was the last agnatic member of the family, but did not succeed as head
Max Emanuel (1968–), adopted by Louis William from the Royal branch of the dynasty, non-agnatic relative through his grandmother Duchess Marie Gabrielle in Bavaria, the fourth daughter of Charles Theodore; has no sons
Franz, Duke of Bavaria (born 1933) his elder brother and head of the whole dynasty, is heir presumptive, but was not adopted by Louis William
Prince Max of Bavaria (born 1937), second son of Albrecht, Duke of Bavaria (1905-1996) and Countess Maria Draskovich of Trakostjan (1904-1969), m. 1967 Countess Elizabeth Douglas (born 1940) and has issue:
Marie Caroline (born 1969), m. 1991 Duke Philipp of Württemberg (born 1964) and has issue.
Helene (born 1972).
Elizabeth (born 1973), m. firstly in 2004 Daniel Terberger (born 1967) and has issue.
Anna (born 1975), m. firstly in 2007 Klaus Runow (born 1964) and has issue. Later divorced and secondly married in 2015 Baron Andreas von Maltzahn (born 1964).
Franz, Duke of Bavaria (born 1933), first son of Albrecht, Duke of Bavaria (1905-1996) and Countess Maria Draskovich of Trakostjan (1904-1969) and the dynasty head, not adopted by his grand-uncle Ludwig Wilhelm, but heir presumptive to his brother