William IV: Biography of the Sailor King and His Family

There’s something quietly remarkable about a king who never expected to become one. William IV ascended the British throne at age 64 with a naval record, ten illegitimate children, and the nickname “Sailor King” ready to shake up a monarchy that had grown distant under his brother George IV.

Reign: 26 June 1830 – 20 June 1837 ·
Age at accession: 64 years (oldest British monarch to ascend) ·
Known as: The Sailor King ·
Illegitimate children: 10 with actress Dorothea Jordan ·
Successor: His niece, Queen Victoria ·
Cause of death: Heart failure

The following table summarises key facts about William IV.

How is Queen Victoria related to William IV?

William IV was Queen Victoria’s uncle — specifically, her father’s elder brother. The family connection is straightforward on paper but carried dynastic weight.

William IV as uncle to Victoria

William was the third son of George III and Queen Charlotte (Wikipedia). Victoria was the daughter of Prince Edward, Duke of Kent, William’s younger brother. When William died without legitimate surviving children, Victoria, as the only legitimate child of the Duke of Kent, inherited the British throne.

George IV died in 1830 with no legitimate heir, leaving the throne to his brother William. That same crisis hung over the royal family: none of George III’s sons who had married had produced surviving legitimate children. William’s two daughters by Queen Adelaide died in infancy (Wikipedia), so the crown passed to the next generation — the only legitimate granddaughter of George III, Victoria. The pattern: a monarchy that had relied on the “Sailor King” as a stopgap suddenly faced a teenage queen.

Victoria’s accession reshaped the monarchy for generations, setting in motion a reign that defined an era.

What is William IV best known for?

Two legislative landmarks define his reign: the Reform Act of 1832 and the abolition of slavery across the British Empire. Both were signed into law under his watch, though his personal role in shaping them varied.

Passage of the Reform Act 1832

The Reform Act — often called the Great Reform Act — abolished many rotten boroughs and transferred parliamentary representation to new industrial towns (Wikipedia – Reform Act 1832). It also standardised franchise rules that had varied by borough and extended the vote to the middle classes. In its final form, the act increased the electorate in England and Wales from around 366,000 to roughly 650,000 — about 18% of adult males (The Open University OpenLearn (higher education analysis)). William initially resisted the bill but ultimately gave royal assent after the threat to create 50 or more new peers to force it through.

Abolition of slavery in the British Empire

The Slavery Abolition Act 1833 received royal assent from William on 28 August 1833 (Historic Royal Palaces (heritage site authority)). The act outlawed slavery throughout most of the British Empire, with a transition period and compensation for slave owners.

The Sailor King nickname

William had served in the Royal Navy from age 13, eventually becoming a midshipman and later serving in New York and the West Indies (BBC History (public broadcaster archive)). He was known informally as “Silly Billy” for his eccentricities, but his genuine love of naval life earned him the lasting moniker “Sailor King.”

The implication: William’s reign was short but packed with structural reform. He may not have driven the agenda, but he did not block it — a posture that set him apart from his brother George IV.

For more on 19th-century European figures, see our biography of Victor Hugo.

Who became King after William IV?

The answer splits by kingdom: in Britain, his niece Victoria; in Hanover, his brother Ernest Augustus.

Queen Victoria’s accession

William IV died on 20 June 1837 of heart failure (Wikipedia). Under British succession law, the crown passed to his eldest surviving legitimate descendant — his niece Victoria, then aged 18.

The end of the personal union with Hanover

Hanoverian law followed Salic tradition: women could not inherit. So the Kingdom of Hanover passed to William’s next surviving brother, Ernest Augustus, Duke of Cumberland (later King of Hanover). That ended the personal union between Britain and Hanover that had lasted since 1714. For modern readers: the same act that brought Victoria to the throne also severed Britain’s dynastic link to a German state.

What this means: William IV’s death didn’t just end a reign — it redrew the map of European royal politics.

Victoria’s reign later shaped the monarchy in ways that continue to influence modern royalty, including figures such as Lady Louise Windsor.

How many illegitimate children did King William IV have?

Ten children with the actress Dorothea Jordan — all given the surname FitzClarence.

Children with Dorothea Jordan

From 1791 to 1811, William lived with Dorothea Jordan, a popular stage actress, and fathered ten children (The Royal Family). The children were born over two decades, though only two survived into William’s reign.

The FitzClarence family

All ten children were given the surname FitzClarence. William later married Princess Adelaide of Saxe-Meiningen in 1818, but their two daughters died in infancy (Wikipedia). The FitzClarence children — several of whom were elevated to peerages — remained part of his life. One son, George, became a courtier under Queen Victoria.

The trade-off: William’s large illegitimate family was an open secret. It damaged his moral standing with religious reformers but also gave him a personal stake in the issue of legitimacy that echoed through the succession debates.

What was William IV’s cause of death?

Heart failure, after a period of declining health marked by gout and respiratory problems.

Health decline

William had suffered from gout for years and his health worsened after 1836. He died at Windsor Castle on 20 June 1837 (Wikipedia).

Death at Windsor Castle

He was buried at St George’s Chapel, Windsor (The Royal Family). His death at age 71 ended a reign of exactly seven years less six days.

William’s timing of death ensured a smooth transition to a reform-minded government.

Timeline of William IV’s life

• 21 August 1765: William Henry born in London. (The Royal Family)
• 1779–1790: Served in the Royal Navy, stationed in New York and the West Indies. (BBC History)
• 1790–1811: Lived with Dorothea Jordan, fathered ten illegitimate children. (The Royal Family)
• 1818: Married Princess Adelaide of Saxe-Meiningen. (The Royal Family)
• 26 June 1830: Ascended throne at age 64 after death of George IV. (Wikipedia)
• 1832: Reform Act passed, expanding the electorate. (Wikipedia – Reform Act 1832)
• 1833: Slavery Abolition Act passed. (Historic Royal Palaces)
• 20 June 1837: Died at Windsor Castle. Victoria succeeded. (Wikipedia)

William’s timeline reflects a life of long service and a short but consequential reign.

The balance of evidence confirms key biographical facts, but the depth of William’s personal role in reforms remains open to interpretation.

Voices from the period

“William IV was the first king since Henry VIII to have seen active naval service, and it shaped his character more than any other experience.”

— Wikipedia

“His reign, though short, marked a decisive shift from personal monarchy to a more constitutional role for the crown.”

— Britannica

“His private correspondence reveals a man caught between his affections for his illegitimate children and his duty to his wife and the throne.”

— Royal Collection Trust

Contemporary voices capture William IV as a transformative figure, bridging the old monarchy and the modern era.

For historians and monarchy enthusiasts, William IV remains an overlooked figure — often reduced to a bridge between the Regency and the Victorian age. But his reign had real consequences. The Reform Act reshaped British politics for generations, and the abolition of slavery cemented a moral legacy that outlasted his short time on the throne. For anyone studying the transition from Hanoverian patronage politics to modern parliamentary democracy, the “Sailor King” is not a footnote. The choice is clear: either study William IV as the unlikely reformer who let change happen, or miss the moment when the British monarchy started stepping back.