They all married quiet late to be honest with some of the grand daughters being in their late 20s, if you want to make as many, the consorts/mothers of monarchs, whether the title is Grand Duchess, Princess, Queens, Empresses or Tsaritsas, here is a massive "Marriage Wank" alternative set up with their 21 granddaughters[*]:
The great Balkan marriages
1)
Princess Victoria of Hesse and by Rhine [3] marries
Crown Prince Rudolf of Austria in 1879, her aged 16, him aged 21.
2) Princess
Sophia of Prussia [1] marrying
Constantine I of Greece [A] in 1889
3)
Princess Margaret of Prussia [1] marries
Ferdinand I of Bulgaria in 1892
4)
Marie of Edinburgh [4] marries
Ferdinand I of Romania [A] in 1893
The great Scandinavian marriage
5)
Viktoria [1] marrying
Gustaf V, King of Sweden in 1882, her aged 16, him aged 23
6) Victoria [2] marrying
Christian X of Denmark in 1886, her aged 18, him aged 16 (her cousin via her mother,
Alexandra of Denmark)
7) Maud [2] marries Haakon VII of Norway [A] but earlier in 1888, her aged 19, him aged 16
8)
Alix of Hesse and by Rhine [3] marries Nicholas II of Russia [A]
Large European Kingdoms
9)
Princess Irene of Hesse and by Rhine [3] marries
Wilhelm II, German Emperor, in 1882, her aged 16, his age 23. [£]
10) Louise [2] marrying
Carlos I of Portugal and the Algarves, in 1885, her aged 18, him aged 22.
11)
Princess Helena Victoria [5] marrying
Victor Emmanuel III of Italy in 1895,
12)
Princess Victoria Eugenie of Battenberg [8] marries
King Alfonso XIII of Spain in 1906 [A]
Small European Kingdoms
13)
Charlotte of Prussia [1] marrying
William II of
Württemberg in 1877, her aged 16, him aged 29
14)
Princess Victoria of Saxe-Coburg and Gotha [4] marrying
Albert I of Belgium in 1899, her aged 23, him aged 24
15)
Princess Elisabeth of Hesse and by Rhine [3] marrying
Alexander, Prince of Orange in 1880. [$]
16)
Princess Marie Louise [5] marries
Frederick Augustus III of Saxony, in 1890, her aged 18, him aged 25.
17)
Princess Alexandra of Saxe-Coburg and Gotha [4] marries
Rupprecht, Crown Prince of Bavaria, in 1896, her aged 18, him aged 27.
18)
Princess Beatrice of Saxe-Coburg and Gotha [4] marries
Franz, Hereditary Prince of Liechtenstein, in 1902, her aged 18, him aged 49. [%]
19)
Princess Margaret of Connaught [6] marries
Louis II, Prince of Monaco in 1900, her aged 18, him aged 30 [&]
Granddaughts of Victoria, marrying Great-grandsons of Victoria
20)
Princess Alice of Albany [7] marries
Wilhelm, German Crown Prince in 1905 [#]
21)
Princess Victoria of Connaught [6] marries
Gustaf VI Adolf of Sweden in 1905 [@]
[*] I'm excluding
Princess Marie of Hesse and by Rhine, who died aged 4 from
diphtheria, for obvious reasons.
[£] - IOTL 1888 she married her aunt
Victoria's other son
Prince Henry, who was only 3 years younger than his brother, the Kaiser.
[$] - Although he dies in 1884, she could become the King/Queen's Mother, when her father-in-law, William III of the Netherlands, dies in 1890
[%] - slightly unusual set up, Franz, on 11 February 1929, succeeds his older brother of
Johann II, Prince of Liechtenstein, who has reigned, unmarried and without issue, since 12 November 1858. In OTL, Franz only marries in 22 July 1929.
[&] A son of
William Hamilton, 11th Duke of Hamilton, through his mother
Mary Victoria Hamilton.
[#] Son of both her own cousin's
Princess Irene of Hesse and by Rhine and
Wilhelm II, German Emperor
[@] Son of her own cousin,
Viktoria and her husband
Gustaf V, King of Sweden
[A] - Same as OTL
[1] - Daughters of
Victoria, Princess Royal
[2] - Daughters of
Edward VII
[3] - Daughters of
Princess Alice
[4] - Daughters of
Prince Alfred,
Duke of Saxe-Coburg and Gotha and
Duke of Edinburgh
[5] - Daughter of
Princess Helena
[6] - Daughter of
Prince Arthur, Duke of Connaught and Strathearn
[7] - Daughter of
Prince Leopold, Duke of Albany
[8] - Daughter of
Beatrice, Princess Henry of Battenberg
[9]
Princess Louise, Duchess of Argyll, was the only one of Victoria's nine children who was childless.
