Robert I (Italian: Roberto Carlo Luigi Maria; 9 July 1848 – 16 November 1907) was the last sovereign Duke of Parma and Piacenza from 1854 until 1859, when the duchy was annexed to Sardinia-Piedmont during the Risorgimento. He was a member of the House of Bourbon-Parma and descended from Philip, Duke of Parma, the third son of King Philip V of Spain and Queen Elisabeth Farnese.

Born in Florence, Robert was the elder son of Charles III, Duke of Parma and Louise Marie Thérèse d'Artois, daughter of Charles Ferdinand, duc de Berry and granddaughter of King Charles X of France. He succeeded his father to the ducal throne in 1854 upon the latter's assassination, when he was only six, while his mother stood as regent.

When Robert was eleven years old, he was deposed, as Piedmontese troops annexed other Italian states, ultimately to form the Kingdom of Italy. Despite losing his throne, Robert and his family enjoyed considerable wealth, traveling in a private train of more than a dozen cars from his castles at Schwarzau am Steinfeld near Vienna, to Villa Pianore in northwest Italy, and the magnificent Château de Chambord in France.

On 5 April 1869, while in exile in Rome, he married Princess Maria Pia of Bourbon-Two Sicilies (1849–1882), daughter of King Ferdinand II of the Two Sicilies. She was his half first cousin once removed, as her father (Ferdinand II) and Robert's maternal grandmother (Princess Caroline Ferdinande of Bourbon-Two Sicilies) were half-siblings, both being children of Francis I of the Two Sicilies.

Maria Pia belonged to the deposed royal family of the Kingdom of Two Sicilies and was thus a Bourbon, like her husband. She gave birth to 12 children, many of whom had intellectual disabilities, before dying in childbirth:

After his first wife's death in childbirth, he remarried on 15 October 1884 to Infanta Maria Antonia of Portugal, daughter of the deposed King Miguel I of Portugal and his wife, Adelaide of Löwenstein-Wertheim-Rosenberg. Maria Antonia was his second cousin once removed, as her paternal grandmother (Charlotte of Spain) and Robert's paternal great-grandmother (Maria Luisa of Spain) were siblings, both being children of Charles IV of Spain and Maria Luisa of Parma. She had another 12 children:

Less than four months after Robert's death in November 1907, the Grand Marshal of the Austrian court declared six of the children of his first marriage legally incompetent (they had severe intellectual disabilities), at the behest of his widow, Maria Antonia. Nonetheless, Robert's primary heir was his son Elias, the youngest son of his first marriage and the only one of his sons by that marriage to beget children of his own. Elias also became the legal guardian of his six elder siblings. While Elias had eight children, seven of whom lived to advanced age, only one of them ever married; she had three children.

The two eldest sons of Robert's second marriage, Sixte and Xavier, eventually sued their older half-brother Elias for trying to obtain a greater share of the ducal fortune. They lost in the French courts, leaving the children of Robert's second marriage with very modest wealth, and the need to earn a living; some of his younger sons served in the Austrian armed forces. Nevertheless, two of the children born of the second marriage made extraordinary marriages: Felix married the grand-duchess of Luxembourg shortly after her accession and is the grandfather of the present duke. Zita married the last Emperor of Austria; the present claimant is her grandson.

•  Duchy of Parma: Grand Prefect of the Sacred Military Constantinian Order of St. George^[3]
•  Spain: Knight of the Order of the Golden Fleece, 19 January 1854^[4]
• Duchy of Modena and Reggio: Grand Cross of the Order of the Eagle of Este, 1856^[5]
•  Kingdom of Bavaria: Knight of the Order of St. Hubert, 1897^[6]
•  Grand Duchy of Hesse: Grand Cross of the Ludwig Order, 9 November 1899^[7]

• Duchy of Parma
• List of Dukes of Parma