Louis I, Grand Duke of Hesse
In 1776, he became engaged to Sophie Dorothea of Württemberg, eldest daughter of Frederick II Eugene, Duke of Württemberg. The engagement was broken off so that Sophia Dorothea could marry Louis's recently widowed brother-in-law Tsarevich Paul Petrovich, son and heir of Catherine II "the Great", Empress of Russia. He received a monetary compensation when the engagement was broken.
Juan Carlos I of Spain
Juan Carlos was married in Athens on 14 May 1962, to Princess Sophia of Greece and Denmark, daughter of King Paul of Greece, first in a Roman Catholic ceremony at the Church of St. Denis, followed by a Greek Orthodox ceremony at the Metropolitan Cathedral of Athens. She converted from her Greek Orthodox religion to Roman Catholicism.