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.
Princess Sophia Hedwig of Denmark
She became the object of marriage prospects early on. As a child, she became engaged to her cousin, John George IV, Elector of Saxony. This was in line with the traditional policy of dynastic marriage between Denmark and Saxony which had at that point become a tradition. In 1689, it was decided that the marriage was to take place two years later. When John George succeeded his father in 1691, he broke the engagement. In 1692, a marriage to the future Joseph I, Holy Roman Emperor, was suggested, and from 1694 to 1697, this plan was the object of considerable negotiations. However, Sophia Hedwig refused to convert to Catholicism despite considerable pressure to do so by her father, which terminated the negotiations. 
Between 1697 and 1699, there was a Danish policy to create an alliance with Sweden through a double wedding between Charles XII of Sweden and Princess Sophia Hedwig of Denmark, and Prince Charles of Denmark and Hedvig Sophia of Sweden (after the marriage of Hedvig Sophia in 1698, she was replaced by Ulrika Eleonora of Sweden). However, though somewhat encouraging to the idea of a Danish match if he would marry, Charles XII did in fact not wish to marry at all, and the Danish-Swedish alliance was further more met with great resistance by the Gottorp Party in Sweden. Sophia Hedwig remained officially unwed, although they were rumors that she entered a secret marriage with her courtier, the noble Carl Adolph von Plessen.