First Cousins: King George IV and King William IV of the United Kingdom

by Susan Flantzer
© Unofficial Royalty 2019

King George IV of the United Kingdom (1762 – 1830)

King Willian IV of the United Kingdom (1765 – 1837)

(All photos credits – Wikipedia unless otherwise noted)

King George IV, born at St. James’ Palace in London, England on August 12, 1762, was the eldest of the fifteen children and the eldest of the nine sons of King George III of the United Kingdom and Charlotte of Mecklenburg-Strelitz. His marriage to his first cousin Princess Caroline of Brunswick was one of the worst ever royal marriages. It is doubtful that the couple spent more than a few nights together as husband and wife. They did manage to have one daughter Princess Charlotte of Wales who would have succeeded her father as queen if she had not died at the age of 21 in childbirth along with her son. From 1811 until his accession, George served as Prince Regent during his father’s final mental illness. George was succeeded by his parents’ third son William. George had no surviving children and the second son Prince Frederick, Duke of York had died childless.

King William IV was the third of his parents’ fifteen children and the third of their nine sons. He was born at Buckingham House (now Buckingham Palace) in London, England on August 21, 1765. William had a happy relationship with actress Dorothea Jordan that lasted over twenty years and produced ten illegitimate children. William and Dorothea’s children married into the British aristocracy and their many descendants include a number of notable people. William’s niece Princess Charlotte of Wales was second in line to the throne and was the only legitimate grandchild of King George III, despite the fact that eleven of his fifteen children were still living. Her death left no legitimate heir in the second generation and prompted the aging sons of King George III to begin a frantic search for brides to provide for the succession.

William, along with his unmarried brothers Edward, Duke of Kent and Adolphus, Duke of Cambridge, all married. 52-year-old William married 25-year-old Princess Adelaide of Saxe-Meiningen. A child of William and Adelaide would have succeeded to the throne as William’s two elder brothers (George IV and Frederick, Duke of York) had no surviving children. Adelaide suffered a miscarriage, gave birth to two princesses who both died in infancy and gave birth to stillborn twin boys. William’s niece Victoria, the daughter of his parents’ fourth son, Prince Edward, Duke of Kent, became his heir.

George and William’s paternal grandparents were Frederick, Prince of Wales and Augusta of Saxe-Gotha-Altenburg. Frederick was the eldest child of King George II of Great Britain and Caroline of Ansbach. However, Frederick predeceased his father and upon the death of George II, Frederick’s eldest son became King George III. George and William’s maternal grandparents were Duke Carl Ludwig Friedrich of Mecklenburg-Strelitz and Princess Elisabeth Albertine of Saxe-Hildburghausen.

George IV and William had 12 paternal first cousins and 11 maternal cousins. They share their first cousins with their siblings Prince Frederick, Duke of York; Charlotte, Princess Royal, Queen of Württemberg; Prince Edward, Duke of Kent; Princess Augusta; Princess Elizabeth, Landgravine of Hesse-Homburg; King Ernest Augustus I of Hanover, Duke of Cumberland; Prince Augustus, Duke of Sussex; Prince Adolphus, Duke of Cambridge; Princess Mary, Duchess of Gloucester; Princess Sophia; Prince Octavius; Prince Alfred; and Princess Amelia.

********************

Paternal Aunts and Uncles of King George IV and King William IV: Children of Frederick, Prince of Wales and Augusta of Saxe-Gotha-Altenburg

Family of Frederick, Prince of Wales painted in 1751 after his death; Front row: Henry, William, Frederick; Back row: Edward, George, Augusta, Dowager Princess of Wales holding Caroline Matilda, Elizabeth, Louisa

********************

Maternal Aunts and Uncles of King George IV and King William IV: Children of Duke Carl Ludwig Friedrich of Mecklenburg-Strelitz and Princess Elisabeth Albertine of Saxe-Hildburghausen

********************

PATERNAL FIRST COUSINS

Paternal First Cousins: Children of Princess Augusta of Wales and Karl Wilhelm Ferdinand, Duke of Brunswick

Augusta of Brunswick, Princess Friedrich of Württemberg ( 1764 – 1788)

Augusta of Brunswick was the eldest of her parents’ seven children. She was the first wife of Prince Friedrich of Württemberg (later Duke of Württemberg 1797 -1803, Elector of Württemberg 1803 – 1806, King of Württemberg 1806 – 1816). Despite having a very unhappy marriage, Augusta and Friedrich had two sons and two daughters including King Wilhelm I of Württemberg.

Friedrich had impressed Empress Catherine II (the Great) while visiting Russia, and she made him Governor-General of Eastern Finland. Four years later, while they were visiting the Empress in St. Petersburg, Augusta asked Catherine for protection from her husband. She claimed that Friedrich was abusive to her, and was having affairs with several men. The Empress took Augusta in and told Friedrich to leave the country. Augusta hoped to obtain a divorce but her father would not permit it. Empress Catherine provided Augusta with a home at Koluvere Castle in Estonia, along with a custodian, Wilhelm von Pohlmann. Soon, Augusta and von Pohlmann began an affair and she became pregnant. Sadly, she went into premature labor and died of blood loss.

Unofficial Royalty: Augusta of Brunswick-Wolfenbüttel, Princess Friedrich of Württemberg

********************

Karl, Hereditary Prince of Brunswick-Wolfenbüttel (1766 – 1806)

Karl was the eldest son and the heir to the Duchy of Brunswick-Wolfenbüttel. However, he had been born blind and mentally disabled. A marriage was arranged for him with Princess Louise of Orange-Nassau but the marriage was childless and Louise was more of a nurse to him than a wife. Karl was eventually forced to renounce his position as heir to his younger brother.

********************

Caroline of Brunswick, Queen of the United Kingdom (1768 – 1821)

Caroline married her first cousin, the future King George IV of the United Kingdom. Despite being first cousins, they had never met. The marriage was very unsuccessful and they separated shortly after the birth of their only child Princess Charlotte of Wales who died at the age of 21 in childbirth.

When George became king, he insisted Caroline would never be queen and wanted a divorce. However, Caroline was popular with the British people who sympathized with her and despised the new king for his immoral behavior. The government introduced a bill in Parliament, the Pains and Penalties Bill 1820, to strip Caroline of the title of queen consort and dissolve her marriage. The reading of the bill in Parliament was effectively a trial of Caroline. The bill passed by 108–99. Prime Minister Robert Jenkinson, 2nd Earl of Liverpool then declared that since the vote was so close, and public tensions so high, the government was withdrawing the bill.

George had made no plans for Caroline to participate in his coronation. On the day of the coronation, Caroline went to Westminster Abbey but was barred at every entrance and finally left. She died three weeks later and had requested that she be buried in her native Brunswick. The official route of Caroline’s cortege through London was to avoid major streets. However, members of the public blocked those streets and forced a new route through the major streets. Caroline was buried at Brunswick Cathedral in Germany alongside her father. Her casket bears the inscription, “Here lies Caroline, the Injured Queen of England.”

Unofficial Royalty: Caroline of Brunswick, Queen of the United Kingdom

********************

Friedrich Wilhelm, Duke of Brunswick-Wolfenbüttel (1771 – 1815)

The fourth son of his parents, Friedrich Wilhelm succeeded his father as Duke of Brunswick-Wolfenbüttel because of the disabilities of his three elder brothers. He had an army career and participated in the Napoleonic Wars. Friedrich Wilhelm married Princess Marie of Baden and had two sons. His wife died of childbed fever (puerperal fever) four days after giving birth to a stillborn daughter. Friedrich Wilhelm was killed in action at the Battle of Quatre Bras, two days before the Battle of Waterloo where Napoleon was defeated once and for all.

********************

  • Georg of Brunswick (1769 – 1811), unmarried, mentally disabled, excluded from the line of succession of the Duchy of Brunswick-Wolfenbüttel
  • August of Brunswick (1770 – 1822), unmarried, blind, excluded from the line of succession of the Duchy of Brunswick-Wolfenbüttel
  • Amelie of Brunswick ( 1772 – 1773), died in childhood

********************

Paternal First Cousins: Children of Prince William Henry of Wales, 1st Duke of Gloucester and Maria, Countess Waldegrave

Background on this side of the family: Prince William Henry of Wales, 1st Duke of Gloucester, a younger brother of King George III of the United Kingdom, secretly married Maria Walpole, the illegitimate daughter of Sir Edward Walpole and his mistress Dorothy Clement. Her grandfather Robert Walpole served as Prime Minister from 1721 – 1741. At the time of the marriage, Maria was the widow of James Waldegrave, 2nd Earl Waldegrave.

King George III’s brothers were a constant headache for him but he was especially annoyed with Prince Henry, Duke of Cumberland. Prince Henry had married a commoner Anne Horton. George III considered Anne Horton inappropriate as a royal bride because she was from a lower social class and German law barred any children of the couple from the succession. George insisted on a new law that would forbid members of the royal family from legally marrying without the consent of the monarch. Although it was unpopular with both George III’s ministers and members of Parliament, the Royal Marriages Act 1772 was passed.

However, King George III did not know that his brother Prince William Henry, 1st Duke of Gloucester had secretly married Maria Walpole in 1766. For six years, King George III believed that his brother William Henry was a bachelor and that Maria was his mistress. In September 1772, five months after the Royal Marriages Act was passed, William Henry found out Maria was pregnant and confessed to his brother that he was married. King George III was quite upset not only by the marriage but also by William Henry’s deception. Because the provisions of the Royal Marriages Act could not be applied retroactively, William Henry and Maria’s marriage was considered valid. Their children were styled His/Her Highness Prince/Princess and used the territorial designation of Gloucester as great-grandchildren in the male line of King George II. However, due to the anger of King George III, Maria, now Duchess of Gloucester, was never received at court.

Princess Sophia of Gloucester (1773–1844)

Sophia was the eldest child of Prince William Henry and Maria Walpole. Her uncle King George III refused to be her godparent because of the deception of her parents’ marriage. She never married. When her brother His Highness Prince William Frederick married their first cousin Princess Mary, daughter of King George III, the king granted him the style His Royal Highness. Sophia was granted the same style the next day.

********************

Princess Caroline of Gloucester (1774–1775)

Princess Caroline’s father Prince William Henry of Wales, Duke of Gloucester became ill with smallpox in March 1775. He immediately ordered that his two daughters (his son had not yet been born) be inoculated against smallpox. At that time, 3% of those receiving the smallpox inoculation died after receiving the inoculation. Sadly, eight-month-old Princess Caroline was one of them. A few years later, Caroline’s first cousins, the two youngest sons of King George III, Prince Octavius and Prince Alfred, also died after receiving the smallpox inoculation.

Wikipedia: Princess Caroline of Gloucester
Unofficial Royalty: Smallpox knew no class boundaries

********************

Prince William Frederick, 2nd Duke of Gloucester (1776–1834)

William Frederick was educated at Trinity College, Cambridge and like his father, had a career in the British Army, attaining the rank of Field Marshal. He was an advocate for the abolition of slavery, served as President of the African Institution and was Chancellor of the University of Cambridge. William Frederick had been encouraged to remain unmarried so that there might be a suitable husband for his first cousin once removed, Princess Charlotte of Wales, the heir to the throne after her father the future King George IV, if no foreign prince proved a suitable match. Charlotte married Leopold of Saxe-Coburg-Saalfeld but within twenty months, Charlotte had died in childbirth along with her son. After Charlotte’s marriage, 40-year-old William Frederick married his first cousin 40-year-old Princess Mary, daughter of King George III of the United Kingdom. The couple had no children.

********************

Paternal First Cousins: Children of Princess Caroline Matilda of Wales and King Christian VII of Denmark and Norway

Background on Caroline Matilda and Christian VII: Princess Caroline Matilda and King Christian VII were first cousins – both were grandchildren of King George II of Great Britain. Christian VII’s reign was marked by mental illness and for most of his reign, he was only nominally king. He publicly declared that he could not love Caroline Matilda because it was “unfashionable to love one’s wife”. Caroline Matilda’s daughter Louise Augusta’s father may have been Christian’s physician Johann Friedrich Struensee. Struensee gained political power and also gained powerful enemies, including Christian VII’s stepmother Queen Dowager Juliana Maria and her son Hereditary Prince Frederik. Juliana Maria directed a plot to overthrow the lovers, which ended with the brutal execution of Struensee and Caroline Matilda’s divorce and banishment. Not quite 20-years-old, Caroline Matilda lost her title of Queen and was forcibly separated from her children whom she never saw again. She died of “a putrid fever and sore throat,” probably scarlet fever, at the age of 23. She was buried at the Stadtkirche St. Marien in Celle next to his great-grandmother Sophie Dorothea of Celle who suffered a similar fate.

King Frederik VI of Denmark (1768 – 1839)

When Frederik came of age, he had to wrest the power from Queen Dowager Juliana Maria and her son Hereditary Prince Frederik, who was ruling as Regent for the mentally disabled King Christian VII. Frederik then ruled permanently as Crown Prince Regent until the death of his father. He married his cousin Princess Marie of Hesse-Kassel, daughter of Prince Carl of Hesse-Kassel and Princess Louise of Denmark. Frederik was a great-grandchild of King George II of Great Britain and Marie was a double great-grandchild of George II. Both of Marie’s parents were children of a daughter of King George II of Great Britain. Frederik and Marie had eight children but unfortunately, six of them, including two boys, died in infancy. Only two daughters survived and both daughters had childless marriages. As he had no sons, Frederik was succeeded by King Christian VIII who was the son of King Frederik’s half-uncle Hereditary Prince Frederik.

********************

Princess Louise Augusta of Denmark, Duchess of Schleswig-Holstein-Sonderburg-Augustenburg  (1771 – 1843)

Louise Augusta was officially the daughter of King Christian VII of Denmark but most likely her biological father was Johann Friedrich Struensee, Christian VII’s physician. When she was only 14-years-old, Louise Augusta married Frederik Christian II, Duke of Schleswig-Holstein-Sonderburg-Augustenburg and had two sons and one daughter. Their daughter Caroline Amalie became Queen of Denmark by marrying the future King Christian VIII of Denmark, son of Hereditary Prince Frederik of Denmark. Louise Auguste’s son Christian August II, Duke of Schleswig-Holstein-Sonderburg-Augustenburg was the father of Prince Christian of Schleswig-Holstein who married Queen Victoria’s daughter Princess Helena. Another of Christian August II’s sons, Frederick VIII, Duke of Schleswig-Holstein, was the father of Princess Augusta Viktoria of Schleswig-Holstein, the wife of Wilhelm II, German Emperor and King of Prussia.

********************

MATERNAL FIRST COUSINS

Maternal First Cousins: Children of Carl II, Grand Duke of Mecklenburg-Strelitz and his first wife Princess Friederike of Hesse-Darmstadt who died in childbirth giving birth to her tenth child who lived only one day

Duchess Charlotte Georgine of Mecklenburg-Strelitz, Duchess of Saxe-Hildburghausen (1769–1818)

Charlotte and her siblings grew up in Hanover, where their father served as governor, on behalf of his brother-in-law King George III of the United Kingdom, who was also King of Hanover. She married Friedrich, Duke of Saxe-Hildburghausen (later Duke of Saxe-Altenburg) and had seven sons and five daughters, including Therese of Saxe-Hildburghausen who became Queen of Bavaria by marrying King Ludwig I of Bavaria.

********************

Duchess Therese of Mecklenburg-Strelitz, Princess of Thurn and Taxis (1773–1839)

Therese married Karl Alexander, 5th Prince of Thurn and Taxis and had three daughters and four sons. Karl Alexander was Roman Catholic. Therese’s aunt Queen Charlotte of the United Kingdom and her husband King George III helped to broker the marriage and were responsible for ensuring that Therese could remain Protestant. Therese also had an illegitimate son and daughter with Maximilian, Graf von und zu Lerchenfeld auf Köfering und Schönberg. She Therese took an active role in the administration of the Princely House of Thurn and Taxis and was also devoted to art and literature.

********************

Duchess Luise of Mecklenburg-Strelitz, Queen of Prussia (1776–1810)

Following her mother’s death in childbirth in 1782, Luise and her siblings were raised mostly by their maternal grandmother, Marie Louise Albertine of Leiningen-Falkenburg-Dagsburg. Luise and her sister Friederike attracted the attention of two Prussian princes. Luise married the future King Friedrich Wilhelm III of Prussia, while Friederike married his brother Ludwig Karl. Luise and Friedrich Wilhelm III had five sons and four daughters including Friedrich Wilhelm IV, King of Prussia; Wilhelm I, King of Prussia, German Emperor; and Charlotte who married Nicholas I, Emperor of Russia. Luise took it upon herself to stay well-versed in the affairs of the country, earning her the respect of her husband’s advisers. While visiting her father in Strelitz, 34-year-old Luise died in her husband’s arms from an unidentified illness.

********************

Duchess Friederike of Mecklenburg-Strelitz, Queen of Hanover (1778–1841)

Friederike married three times and had a total of ten children. When her sister Luise married the future King Friedrich Wilhelm III of Prussia, Friederike married his brother Ludwig Karl and had two sons and one daughter. The marriage between Friederike and Ludwig was not very happy, with both of them allegedly having affairs. Prince Ludwig died of diphtheria just two days after their third wedding anniversary, leaving Friederike an 18-year-old widow with three children. Two years later, Friederike accepted a proposal from Prince Adolphus of the United Kingdom, Duke of Cambridge, her first cousin. Apparently, Friederike had not very lonely. Despite her unofficial engagement to Adolphus, she soon found herself pregnant with the child of Prince Friedrich Wilhelm of Solms-Braunfels. The couple married and had five sons and one daughter. Within a few years of the marriage, the couple had drifted very far apart and were given permission to divorce but remained married.

Friederike fell in love with another first cousin, Prince Ernest August of the United Kingdom, Duke of Cumberland, a son of King George III of the United Kingdom and Friederike’s aunt Charlotte. Divorce proceedings were started but Friederike’s second husband Prince Friedrich Wilhelm of Solms-Braunfels suddenly died and Friederike soon married Ernest August. After two stillborn daughters, the couple had one son. When Ernest Augustus’ brother King William IV died, he was succeeded by his niece, Victoria, as Queen of the United Kingdom but because Hanover did not allow for female succession, Friederike’s husband succeeded him as King Ernst August I of Hanover, and Friederike became Queen.

********************

Georg, Grand Duke of Mecklenburg-Strelitz (1779–1860)

Georg married Princess Marie of Hesse-Kassel, the daughter of Landgrave Freidrich of Hesse-Kassel and Princess Caroline of Nassau-Usingen and had four children including Friedrich Wilhelm, Grand Duke of Mecklenburg-Strelitz who married his first cousin Princess Augusta of Cambridge and Princess Caroline Mariane who married the future King Frederik VII of Denmark. When Georg succeeded his father as Grand Duke of Mecklenburg-Strelitz, he found the grand duchy in great debt and in need of much rebuilding. He abolished serfdom and throughout his reign worked to raise the standards of education, building schools and instituting compulsory education. He made vast improvements to the infrastructure which would help to energize the grand duchy’s economy.

********************

  • Duchess Caroline Auguste of Mecklenburg-Strelitz (1771–1773), died in childhood
  • Duke Georg Carl of Mecklenburg-Strelitz (1772–1773), died in childhood
  • Duke Friedrich Georg of Mecklenburg-Strelitz (born and died 1774), died in infancy
  • Duke Friedrich Karl of Mecklenburg-Strelitz (1781–1783), died in childhood
  • Duchess Augusta Albertine of Mecklenburg-Strelitz (born and died 1782), died in infancy along with her mother

********************

Maternal First Cousins: Children of Carl II, Grand Duke of Mecklenburg-Strelitz and his second wife Princess Charlotte of Hesse-Darmstadt who was the sister of Carl’s first wife. Like her sister, Charlotte died in childbirth.

Duke Karl of Mecklenburg-Strelitz (1785–1837)

Karl’s mother died as a result of his birth. He had a career in the Prussian Army and never married. He fought in the Napoleonic Wars and attained the rank of a Lieutenant General. For the last ten years of his life, Karl was President of the Prussian State Council, an advisory body in the Kingdom of Prussia.

********************

This article is the intellectual property of Unofficial Royalty and is NOT TO BE COPIED, EDITED, OR POSTED IN ANY FORM ON ANOTHER WEBSITE under any circumstances. It is permissible to use a link that directs to Unofficial Royalty.

Works Cited

  • Lundy, D. (2019). Main Page. [online] Thepeerage.com. Available at: http://www.thepeerage.com/. (for genealogy information)
  • Unofficial Royalty. (2019). Unofficial Royalty. [online] Available at: https://www.unofficialroyalty.com. (for biographical and genealogy information)
  • Wikipedia. (2019). Main Page. [online] Available at: https://en.wikipedia.org/.  (for biographical and genealogy information)