The royal descendants of Victoria (Queen of the United Kingdom) and of Christian IX (King of Denmark) currently occupy the thrones of Belgium, Denmark, Luxembourg, Norway, Spain, Sweden and the United Kingdom.
At the outbreak of the First World War their grandchildren occupied the thrones of Denmark, Greece, Norway, Germany, Romania, Russia, Spain and the United Kingdom.
For this, Queen Victoria was nicknamed "the grandmother of Europe" while King Christian IX was nicknamed "Father-in-law of Europe".
Of the remaining kingdoms of Europe today, only Willem-Alexander of the Netherlands descends neither from Queen Victoria nor King Christian IX.
Queen Victoria arranged the marriage of her eldest son and heir-apparent, the future Edward VII, to Alexandra of Denmark, the eldest daughter of King Christian IX, which took place on 10 March 1863.
Among their six children were George V (who was also Emperor of India throughout his reign) and his sister Maud of Wales (who would later marry their cousin King Haakon VII of Norway, another grandchild of Christian IX, on 22 July 1896).
However, these two marriages were not the only unions amongst and between descendants of Victoria and Christian IX.
The second son of Christian IX, Prince William, became King of Greece as George I shortly after his sister Alexandra's marriage due to this new connection with the British Royal Family.
On 27 October 1889 his son, later Constantine I of Greece, married Sophia of Prussia, a granddaughter of Victoria, forging another union between descendants of the British queen and the Danish king.
In 1865, Christian IX's second daughter, Princess Dagmar, became engaged to Tsarevich Nicholas of Russia, son and heir of Tsar Alexander II.
Following the untimely death of her fiancé, Dagmar married Nicholas's younger brother, the Tsarevich Alexander in 1866, taking the Russian name Maria Feodorovna. Her son, Nicholas II of Russia, married Alix of Hesse and by Rhine, yet another granddaughter of Queen Victoria, on 26 November 1894, and she became empress-consort as Alexandra Feodorovna.
Other grandchildren became monarchs in their own right or consorts.