The Cousins Who Started World War I: The Victorian Family Tree

By Andrew Koch Premium
This illustration shows Queen Victoria (center, seated) among her children and grandchildren. Image courtesy Wikimedia Commons

Archduke Franz Ferdinand’s assassination in 1914 drew most major European powers into war. But some of the sparring countries had an unusual thing in common: Their leaders were cousins. This made World War I something of a family affair. We have the United Kingdom’s Queen Victoria—called the “Grandmother of Europe”—to thank for this historical anomaly. Let’s take a look at the Victorian family tree to see just how her grandchildren fought each other in the “war to end all wars.”

Forming marriage alliances

By viewing the Victorian family tree, we can see how Queen Victoria's grandchildren became the most important figures of World War I.
This partial Victorian family tree, created in, shows how the children of Victoria’s three eldest children became (or married) the monarchs of combatant countries. Germany’s Wilhelm II (highlighted in black) descends from Victoria’s eldest daughter Vicky, while the United Kingdom’s George V is Victoria’s grandson via Edward VII. Alexandra, one of Victoria’s granddaughters, married the man who became Russia’s Tsar Nicholas II.

Queen Victoria and her husband, Prince Albert, wanted to expand British influence in Europe. Themselves first cousins, they knew firsthand the importance of consolidating royal power via marriage. They had nine children, each of whom they married off to important European royal families. These children (and the grandchildren that resulted from the marriage) spread Victoria’s genes all around the continent:

  • Victoria (called “Vicky”) married into Prussian nobility. Her husband, Frederick III, died after serving just 99 days as German emperor. Their son, William, became Germany’s Kaiser Wilhelm II, and their daughter Sophia married Constantine, the future king of Greece.
  • Albert Edward inherited Victoria’s crown upon her death, becoming King Edward VII of the United Kingdom. He married Alexandra of Denmark, whose father ascended to the Danish throne the same year. Their son George V inherited the British crown, while their daughter Maud married Prince Carl of Denmark (later King Haakon VII, king of Norway).
  • Alice had seven children before dying young, at the age of 35. One of them (“Alix,” or Alexandra) married the man who would become Tsar Nicholas II, emperor of Russia.
  • Alfred ruled as Duke of Saxe-Coburg and Gotha (a German Duchy). His daughter Marie became queen of Romania when she married Crown Prince Ferdinand (later, Ferdinand I).
  • Helena married the prince of the German province of Schleswig-Holstein. Though she had four children who lived to adulthood, none of them had legitimate children.
  • Louise died without having children. She married a British commoner named John Campbell, who became the Duke of Argyll.
  • Arthur served as governor of Canada. His daughter Margaret married Crown Prince Gustaf Adolf of Sweden, but died decades before Gustaf ascended to the throne.
  • Leopold was made Duke of Albany, but died young. His son, Charles Edward, was stripped of his titles after fighting for the Germans in World War I.
  • Beatrice married a German prince. Her daughter Victoria Eugenie married King Alfonso XIII of Spain.

The Queen hoped this complicated web of alliances would keep Britain powerful and Europe peaceful. But once Victoria died in 1901, the familial connections began to degrade.

Family feud

When World War I broke out, Queen Victoria’s grandchildren served as (or had married) the kings or emperors of the UK, German, Norwegian, Romanian, Russian, Greek, Swedish and Spanish governments:

  • King George V of the United Kingdom (Victoria’s grandson via Albert Edward/Edward VII)
  • Kaiser Wilhelm II of Germany (Victoria’s grandson via Vicky)
  • King Haakon VII of Norway (husband of Victoria’s granddaughter, Maud)
  • Ferdinand I of Romania (husband of Victoria’s granddaughter, Marie)
  • Tsar Nicholas II of Russia (husband of Victoria’s granddaughter, Alexandra)
  • King Constantine I of Greece (husband of Victoria’s granddaughter, Sophia)
  • Crown Prince Gustaf Adolf of Sweden (husband of Victoria’s granddaughter, Margaret)
  • King Alfonso XIII of Spain (husband of Victoria’s granddaughter, Victoria Eugenie)

The war saw Germany (along with Austria-Hungary and the Ottoman Empire) square off against a coalition of allies including the United Kingdom, Romania and Russia. This meant Wilhelm II was at war with his cousin George V and cousins-in-law Nicholas II and Ferdinand I.

Several of Victoria’s grandchildren and great-grandchildren died in World War I. Beatrice’s son sustained critical injuries in the war, as did two of Vicky and Frederick’s grandsons. (The latter, notably, were Kaiser Wilhelm’s nephews.)

Some leaders were content to let their cousins duke it out. Norway, Sweden and Spain remained neutral in the war, and Constantine I abdicated when it became clear he couldn’t guarantee Greek neutrality.

Heavy is the head that wears the crown

While being a member of the Victorian family tree certainly had its perks, Victoria’s descendants faced numerous challenges. She carried a gene for hemophilia, a deadly genetic blood disorder that Victoria passed down through the generations. Tsar Nicholas’ son Alexei famously had the disease, as did Victoria’s son Leopold and several other royal family members.

Moreover, most of these monarchies didn’t survive the 20th century, when democracy and communism swept across Europe. Kaiser Wilhelm II abdicated after Germany’s defeat in World War I, and Bolsheviks drove Tsar Nicholas II (and thus, his wife Alexandra) out of power and murdered his family. Marie and Ferdinand I’s grandson, King Michael I of Romania, was twice forced to abdicate and lived most of his life in exile. Constantine I of Greece likewise twice abdicated, and Victoria Eugenie and Alfonso narrowly survived an assassination attempt on their wedding day in 1906.

Modern monarchs

Several of Victoria’s issue remain on several European thrones today. King Harald V of Norway, King Carl XVI Gustaf of Sweden and King Felipe VI of Spain all descend from Victoria and Albert.

As you might expect, Victoria’s descendants include the United Kingdom’s Queen Elizabeth II and her husband, Prince Phillip. In fact, both are Victoria’s great-great-grandchildren, making them second cousins to each other. Elizabeth inherited the crown from her father George VI (a descendant of Albert Edward/Edward VII), while Phillip descends from Victoria’s daughter Alice. Learn more about Queen Elizabeth’s family history.