Before Margaret Tudor married James IV of Scotland in 1503, there was another English Margaret who married a king of Scotland. And while this marriage didn’t bring about Great Britain, it did put the wheels in motion for what would lead to the wars between England and Scotland during the reign of Margaret’s brother, Edward I, solidifying centuries of tension between the two countries.

Margaret was born to Henry III and Eleanor of Provence at Windsor Castle on September 29, 1340. She was her parents’ second child, following her brother, Edward, born the year before. While an exact year of birth for Margaret’s mother isn’t known, it’s believed that she was likely around 16 or 17 at the time of her daughter’s birth.

Eventually, the royal nursery would be rounded out by the birth of another daughter, Beatrice, in 1342, a second son, Edmund, in 1345, and a third daughter, Katherine, in 1353. Four additional sons might have been born in-between these children, however their existence is debatable and all would have died young.

Margaret’s Scottish fate was decided when she was still in the nursery. In 1244, Henry III met with Alexander II of Scotland the two hashed out a marriage agreement between Margaret and Alexander’s son, another Alexander. Alexander II was familiar with the Plantagenets already, having married Princess Joan, daughter of King John, back in 1221 after her mother, Isabella of Angouleme, “stole” her betrothed, Hugh X of Lusignan, from her the year before.

The betrothal was solidified that same year, when the bride and groom were four years old. There is little information about Margaret over the next seven years, though records indicate that she and her siblings occasionally participated in public events. The unhappiness of their parents’ marriage may have put additional strain on family dynamics – the eight-year gap between the birth of Edmund and the birth of Katherine was due to a prolonged estrangement between king and queen.

The dysfunction that permeated the family was even evident during Margaret’s wedding on December 26, 1351 at York Minster when Henry had a public dispute with Simon De Montfort, his brother-in-law, over money. It was an ignoble start to Margaret’s marriage, one that set the tone for the next several years for the young couple. While we don’t have a description of Margaret’s gown at her wedding, we do have one for her mother, who wore silk robes trimmed in gold and an ermine cloak. Fittingly, Eleanor was both widely detested and a bit of a fashion plate.

Margaret was 11 when she first arrived in Scotland and her new husband only 10. Two years before he had succeeded his father on the throne as Alexander III, but due to his age a minority government was put in place under he reached legal majority. Due to their age, the couple were kept apart and rarely allowed to interact, which upset Margaret who quickly grew fond of her husband. The isolation did nothing to help acclimate the young queen, who soon took to complaining to her parents about how uncomfortable her accommodations were, the cold and how the Scots weren’t respectful enough of her rank.

Most grating of all was the extent to which her movements were restricted, including not being allowed to return to England to visit her family. Apparently, due to her dislike of Scotland being common knowledge to the government, there was a fear that she would refuse to return. The matter came to a head in 1255 when Eleanor sent an envoy, Reginald of Bath, to report back on the truth of her daughter’s circumstance. Reginald reported back that Margaret wasn’t exaggerating – and was then promptly poisoned by the Scottish government.

Henry and Eleanor responded by heading to Scotland at the head of an army where a deal was sorted out in which the government agreed Alexander and Margaret could consummate their marriage now that they were both 14 and Margaret was free to visit her family whenever she pleased. Later that year, Margaret spent time with Eleanor in Northumberland and soon after that, Margaret and Alexander spent an extended stay in England.

In 1257, Henry was prompted to intervene on his daughter’s behalf yet again when she and Alexander were held captive by a powerful political family who wanted to all non-Scots expelled from the country. Henry again lent military support and the couple were soon freed.

In the summer of 1260, Margaret became pregnant for the first time and traveled to England to be with her mother for the birth. On February 28, 1261, Margaret was delivered of a daughter at Windsor Castle who she named after herself.

A second child, Alexander, was born on January 27, 1264, finally providing an heir. He was followed, eight years later, by another son, David, on March 20, 1272.

The following year Margaret was accidentally involved in the killing of an equerry. She and a group of her ladies-in-waiting were apparently lounging near a river and, as a joke, she pushed one of her equerries in, thinking he would easily be able to get back out. Instead, he and a servant who jumped in after him to help were caught up in a current and drowned. The incident traumatized Margaret, who reportedly spoke in great detail about it with her confessor.

In 1274, Alexander and Margaret traveled to England once more for the coronation of her brother, Edward I, and his wife, Eleanor of Castile. It would prove to be Margaret’s last visit home. On February 26, 1275, Margaret passed away at Cupar Castle at the age of 34.

Margaret missed out on how her children’s lives unfolded, which may have been a small blessing. Her daughter, Margaret, married Eric II of Norway in Bergen in 1281. She died two years later of childbed fever after giving birth to a daughter, also named Margaret. That child would become incredibly important to Scotland given that both Alexander III and Margaret’s sons died young and without children (Alexander in 1284 and David in 1281).

While Alexander III remarried in the hopes of begetting a son – and purely for that reason given that by all accounts he was heartbroken by Margaret’s death – the marriage was short-lived and childless thanks to his death in 1286. The sole heir to the throne was thus a Norwegian princess who became known in Scotland as the “Maid of Norway.”

The young Princess Margaret was duly sent to Scotland at the age of seven, but died of sea sickness shortly after landing.

What followed was essentially a monarchical lottery system in which several applicants put their names forward for review. In the end, England’s Edward I played a role in selecting the eventual choice, but his decision was premised on a desire to subjugate Scotland and when that didn’t work it led to decades of war towards the end of Edward’s reign. He would eventually become known as the “Hammer of Scotland” and Scotland’s hatred of the English lasted centuries after his reign ended.