The title of Duke of Chaulnes, a French peerage, is held by the d'Albert family beginning in 1621.
History
The Duchy of Chaulnes was established by a letters patent of January 1621, registered on 6 March 1621 at the Parliament of Paris in favour of a younger brother of Charles d'Albert, Duke of Luynes, Honoré d'Albert, Marshal of France in 1619, known as the Marshal de Cadenet. On 14 January 1620 he married Charlotte Eugénie d'Ailly who was the heir to a family holding the titles of Count of Chaulnes, Vidame d'Amiens and Baron de Picquigny. The marriage contract stipulated that their heirs would take the name and arms of Ailly, which indeed happened; their children took the surname of d'Albert d'Ailly. The first Duke of Chaulnes est known by the bloody repression of the Breton people in 1675 The first Duke of Chaulnes had several sons; only one was married, however, and he himself sired only girls. He became the second duke, and when he died in 1653, lacking male progeny, the title passed to a minor who became the third Duke. In 1667, to avoid the title passing into disuse, the third duke, at the request of his mother, Charlotte d'Ailly, named his heir as the Duke of Chevreuse, second son of the Duke of Luynes. This was stipulated in the Duke of Chevreuse's marriage contract which also stipulated that the title would pass to the youngest child of the marriage and, in case the male line subsequently ended, to the youngest of that name who held the arms of the d'Albert family. Thus two distinct houses were created: Luynes, which the Duke of Chevreuse inherited from his father in 1688, and Chaulnes, which remained distinct and separate from the former until the direct line of inheritance came to an end. In that case, the two houses should be reunited until it was possible to separate them again. Thus, at the time at which the first line of d'Albert d'Ailly ended with the death of the third Duke of Chaulnes in 1698, the Duchy of Chaulnes went to the Duke of Chevreuse, who in the meantime had become the Duke of Luynes. In 1694, he passed the duchy of Luynes to his eldest son Charles Honoré on the occasion of his marriage, and assigned the Duchy of Chaulnes to his younger son Charles Francis, Vidame Amiens, also on the occasion of his marriage in 1710. This transmission was confirmed by letters patent in October 1711, registered on 1 December 1711, which established Chaulnes as a duchy for the first time in favour of Charles Francis. Charles Honoré's son was killed in 1704 and it was his grandson Charles Philippe who inherited the duchy of Luynes. In 1732, the 4th Duke of Luynes, Charles Philippe, and the 4th Duke of Chaulnes, Louis Auguste, made an agreement whereby the former relinquished his rights over the duchy of Chaulnes, while the latter received confirmation which said that if the Duchy of Chaulnes should return to the house of Luynes, it would pass to the youngest child of that family, and then remain in the direct male line. In 1792, the title of Duke of Chaulnes returned to the Dukes of Luynes until 1852, at which time a third branch of the d'Albert d'Ailly family was founded which took the title of Duke of Chaulnes as a courtesy title. This line ended in 1980. The title is carried today as a courtesy title by a younger brother of the current Duke of Luynes.
