Maria Feodorovna (Sophie Dorothea of Württemberg)
Born Duchess Sophie Dorothea of Württemberg, she was a daughter of Friedrich II Eugen, Duke of Württemberg and his wife, Friederike Dorothea of Brandenburg-Schwedt. She belonged to a junior branch of the House of Württemberg and grew up in Montbéliard receiving an excellent education for her time and station. In 1776, when Grand Duke Paul (the future Paul I of Russia), became a widower, Sophie Dorothea was chosen by Frederick II of Prussia, her maternal great uncle, and by Empress Catherine II of Russia, as the ideal candidate to be Paul’s second wife. They met in a state dinner in Berlin and their engagement was quickly arranged.
Morganatic marriage
Perhaps the most famous example in modern times was the 1900 marriage of the heir to the throne of Austria-Hungary, Archduke Franz Ferdinand, and Bohemian aristocrat Countess Sophie Chotek von Chotkowa. The marriage was initially resisted by Emperor Franz Joseph I, but after pressure from family members and other European rulers, he relented in 1899 (but did not attend the wedding himself). The bride was made Princess (later Duchess) of Hohenberg, their children took their mother's new name and rank, but were excluded from the imperial succession. The Sarajevo assassination in 1914, killing both the Archduke Franz Ferdinand and his wife Sophie, triggered the First World War.