Who married Duchess Helene of Mecklenburg-Schwerin?

Duchess Helene of Mecklenburg-Schwerin (Helene Luise Elisabeth; 24 January 1814 – 17 May 1858) was a French Crown Princess after her marriage in 1837 to the eldest son of Louis Philippe I. She is known as the mother of the future Count of Paris and Duke of Chartres.

Her descendants include present-day pretenders to the throne of France, Romania and Italy, and the kings of Spain and Belgium.

Prince Ferdinand Philippe, Duke of Orléans (Ferdinand Philippe Louis Charles Henri Joseph; 3 September 1810 – 13 July 1842) was the eldest son of King Louis Philippe I of France and Maria Amalia of Naples and Sicily. He was born in exile in his mother's native Sicily while his parents were the Duke and Duchess of Orléans. Ferdinand Philippe was heir to the House of Orléans from birth. Following his father's succession as King of the French in 1830, he became the Prince Royal of France and Duke of Orléans. He died in 1842, never to succeed his father or see the collapse of the July Monarchy and subsequent exile of his family to the United Kingdom.