The longest-reigning monarch in the world was Sobhuza II of Swaziland, who ruled for 82 years and 254 days. It sounds nearly impossible, but Sobhuza was only six months old at the time of his accession. The longest-reigning female monarch was the formidable Eleanor of Aquitaine who ruled over the Duchy of Aquitaine in her own right. She lived to be 82 years old, which in medieval times was ancient. Eleanor reigned for 66 years and 358 days. Eleanor was first married to Louis VII of France, but the marriage was not a success. It produced two daughters, and their marriage was annulled in 1152. She married Henry II of England in 1154 and gave birth to a further eight children. She died on 1 April 1204 and is buried at Fontevraud Abbey in France. Eleanor’s record was beaten by Queen Elizabeth II in early 2019.
Taking a look at other female monarchs on the list, you can also find Wilhelmina of the Netherlands, who was only 10 when she became Queen. She ruled for 57 years and 258 days, before abdicating in favour of her daughter Juliana. Therefore her reign could have been longer, but I think abdicating can be a wise choice. Wilhelmina was born to William III, King of the Netherlands and Emma of Waldeck and Pyrmont. Her father had been married before and had three sons, but all but one had died when Wilhelmina was born. Upon his death, she became her father’s heiress. She married Duke Henry of Mecklenburg-Schwerin, and they had a single child, Juliana, after numerous miscarriages and stillbirths. She died on 28 November 1962 and is buried in the New Church in Delft.
Another woman on the list is Joanna of Brabant, Duchess of Brabant in her own right. She reigned for 50 years and 331 days. Joanna was born on 24 June 1322 to John III, Duke of Brabant and Marie d’Evreux. Her parents also had three sons, but they all died young, so Joanna became her father’s heiress. She married firstly to William IV, Count of Holland who died in battle. They had a single son, who also died young. Her second marriage was to Wenceslaus of Luxembourg. Upon Joanna’s death, the Duchy of Brabant passed to her great-nephew Antoine, who was the second son of her niece, Margaret III, Countess of Flanders. She was buried in the Carmelite Church in Brussels, but her tomb has been destroyed, unfortunately.
Another woman on the list is Joanna of Castile. She was the daughter of Isabel of Castile and Ferdinand II of Castile. She had a brother, who died in his teens and Joanna as the eldest surviving daughter became her parents’ heiress after her elder sister died in childbirth and her son died in 1500. Her father remarried after her mother’s death intending to father a male heir and to keep their lands from being united. However, no male heir was born, and Joanna was the definite heiress of both their lands. Joanna suffered from a fragile mental health and is often remembered as ‘Joanna the Mad’. She spent many years in confinement before finally dying on 12 April 1555 at the age of 75.
As for the United Kingdom, Queen Victoria was the longest-reigning British monarch until 2015 when she was beaten by Queen Elizabeth II. Queen Victoria’s record stood at 63 years and 216 days.