The House of Stuarts brought about a lot of firsts, though they’re rarely given credit for it. Indeed, stuck between the Tudors and the forebears of today’s Royal Family, they’re an in-between group of monarchs that have always failed to inspire quite as much interest as their peers. And that’s a shame, because they were certainly as dysfunctional and dramatic as those that came before and after. Even more, they were just as politically significant to the evolution of Great Britain.

Among those firsts was the only set of true co-monarchs to ever rule, albeit briefly. In 1689 Queen Mary II was declared sovereign alongside her half-Dutch, half-English husband, William III. Unlike Mary I whose Spanish-born husband was only ever truly king in name (and spent limited time in England), or Elizabeth I who declined to marry at all, or even Mary Stuart, Queen of Scotland who deprived her husband of the crown matrimonial, Mary and William approached their British rule as legal equals. It was an extraordinary display in the 17th century, and one that has never again been replicated.

At the dawn of 1689, William and Mary had been married for just over 11 years. Prior to that they had lived in The Hague where William served as the Stadtholder of Holland, Zeeland, Utrecht, Gelderland and Overijssel and Mary his consort. More commonly, they were (and are) known as William and Mary of Orange in a nod to the style of William’s name at birth. Wildly ill-matched in temperament, childless and first cousins, there were any number of factors working against them – nevertheless, they grew into a good team both professionally and personally. Arguably, without the other, their success would have been impossible.

William was born on November 14, 1650, the son of 24-year-old William II, Prince of Orange and 19-year-old Mary Stuart. On his father’s side he was thoroughly Dutch and German, while on his mother’s he was a member of the House of the Stuart. As of his birth that didn’t meant too much, for less than two years before, his grandfather, Charles I, had been executed at the close of the Civil War and the rest of the family went into exile on the continent, seeking refuge through the courts of Europe. Thanks to an early marriage at the age of just 12, Mary managed to escape this fate, but she worried constantly about her brothers, to whom she frequently gave money she could ill-afford.

As of when her son was born, Mary faced a more immediate crisis: the death of her husband. The elder William died just eight days before the birth of his heir, his untimely illness and passing prompting his wife into premature labor and resulting in an undersized, sickly infant who many feared wouldn’t live to see his first birthday. He did, but the palace in which he spent that year was literally draped in black, from the bed in which he was born to the cradle in which he was placed. Perhaps it’s not surprising, then, that he grew into a serious, even melancholy, young man.

There is debate over William’s relationship with his British mother. The general consensus is that she exhibited little maternal feeling towards her son, though it may be a bridge too far to say she didn’t love him. Certainly she didn’t exhibit the traditional affection which may have been expected. Quite possibly, Mary was depressed. Even a decade after her marriage, she was often homesick for England, she was unpopular with the Dutch people and court and she was traumatized by the untimely death of her husband. Even the name of her son was taken from her – when she chose “Charles” in honor of her father and brother, she was overruled by her mother-in-law. Taken alongside the fact that nobody expected the infant to live, perhaps it’s less surprising that Mary never fully bonded with him.

But if she failed her son in providing day-to-day care, she was firm in thinking about his future – namely, she desired that he would one day be named a king with the support of her brother when he reclaimed the throne. When Charles II and the rest of the Stuarts were welcomed back to England in 1660, Mary prepared to join them there in celebration – well, that, and she wanted to express her immense displeasure with her brother, James, Duke of York, having married one of her former maids. The bride in question, Lady Anne Hyde, soon revealed herself to also be pregnant. Unfortunately Mary’s reunion with her family was brief. She was dismayed by the fog and poor air quality when she arrived, saddened by the abrupt death of her younger brother, Henry, Duke of Gloucester and soon took ill herself with smallpox. She died at the age of 29 on December 24, 1660 and was buried in Westminster Abbey.

Back in Orange, William’s solemn upbringing continued. He was kept away from children his own age, surrounded by adults who viewed him less as a child then as a future leader and his days were made up of lessons with a heavy focus on military preparation. Believed delicate, he was introduced only later in life to athletic pursuits, though the only one to which he took was hunting, a lifelong passion.

In November 1670 William received permission to travel to England, overriding protestations that too many of his relatives had caught ill and died following their visits. At first, Charles II, warmly received him, but as the days went by and William showed himself to be polite, but slightly contemptuous of the overindulgence of the English court, he grew wary. William offered no promise to take a bride of his uncle’s choosing, he didn’t drink and he rarely smiled. At one point Charles and a few courtiers got him drunk for their own amusement – so drunk in fact that he broke a window to the chamber containing the Queen’s maids of honor and had to be pulled back from entering. Unused to alcohol, he was in bed with a hangover for multiple days afterward and Charles sent him a hangover cure of chocolate, egg and milk.

In the end, he was formally acknowledged a successor to the throne after James, the Duke of York, and his two cousins, Mary and Anne of York. As for Mary, who would have been eight, they never met.

The idea of William and Mary marrying was floated about for years before it became serious, and even as each were considered for other matches. Born in 1662 to the Duke and Duchess of York, it wasn’t until her mother died in 1671 having only produced two daughters (Anne was born in 1665) that the possibility Mary would end up on the throne became a distinct possibility. Charles II and Catherine of Braganza remained childless, and though James of York remarried in 1673 to the Italian Mary Beatrice of Modena, her first four pregnancies ended in miscarriage, stillbirth, infant death and another daughter.

In 1676, William was 26, had been stadholder for four years and was ready to contemplate marriage. Personally, he took issue with the low birth of Anne Hyde, knowing full well she had once served his mother, as well as the promiscuity of James, who many believe suffered from venereal disease. Then there was the fact that his own mother, another Mary Stuart, had been so unpopular. Nevertheless, Mary brought him closer to the English throne and failing that, marriage to her increased his influence with Charles II and the possibility of being named king of his own lands.

William arrived in England in October 1677 to be hosted by his uncles as they negotiated his marriage. Charles hoped to use the match as a reward for moving William away from his alliances with Austria and Spain and towards his own friendly relationship with France, but the younger man was only there for one thing: a Stuart bride. Unfortunately for William, the primary objector to the union was James, who had long since converted to Catholicism and wanted a Catholic husband for his daughter, a matter in which he believed he had his brother’s support. But unfortunately for James, a growing segment of Charles’s councilors were eager to distance the King from the French and thought a marriage alliance with the Dutch the perfect way to begin.

After a few days of William behaving coolly, Charles learned that his nephew had little intention of undergoing serious conversation until he had the opportunity to meet his future bride. With that, the court moved to London and he was finally introduced to his cousin.

Mary was 15, four inches taller, pretty and well-mannered. She had grown up in the indulgent atmosphere of her father’s household where most of her socialization came from her younger sister and stepmother. Mostly isolated and used to death thanks to the loss of numerous siblings and her mother, she was similar to William in that she well-understood loneliness. But what manifested itself in him as gravity showed up in her as a tendency to be overly emotional and sensitive. Likely the image of her cousin, significantly older, small, scarred from a bout of smallpox two years prior and unfashionable seemed wholly foreign and unappealing, but she was well-versed in court etiquette and pleased the Prince with her manners.

William was set on marrying her, Charles was set on negotiating a peace with France and Mary was waiting to hear word of what would happen to her. William and Charles ended up in a stand-off of which would come first – marriage or politics – which William won. Charles gave his assent to the match and as the negotiators were congratulating themselves, Mary responded to the news by weeping in her bedroom all afternoon. Though no one asked her, she had little desire to become the next Princess of Orange.

She was given two weeks to prepare for her wedding and departure, aided by her stepmother and aunt. On November 4, William and Mary were married privately in Mary’s bedchamber in St. James’s Palace in the presence of their family. Mary cried through the ceremony, Mary Beatrice was heavily pregnant with her fourth child, James was morose and Anne was upset her sister was leaving. Charles MC’d the event, joking that the officiator should hurry lest Mary Beatrice go into labor and produce the son who would make the match less desirable. Needless to say, it wasn’t well-received.

Three days later, Mary Beatrice indeed gave birth to a son and William, incredibly annoyed by the child, was asked to stand as godfather. He would have his way in the end – shortly after his birth the infant was visited by Anne, who, recovering from smallpox, kissed him and passed on the disease. The child was dead by December 12 and William and Mary had their first quarrel when he ordered her to vacate her apartments in St. James’s to avoid illness and she insisted on nursing her sister.

Though the marriage was popular with the English public, by the time the couple departed London on November 19, all of court noticed William seemed bored by his wife, rarely visited her and mostly ignored her when they were in public together. As she said her goodbyes, Mary was once again in tears.

The couple made their state entry into The Hague on December 14 to ringing bells, cheering crowds and firing guns. Her beauty, shy smile and manners ensured that Mary’s first impression on her people was by far better than that of her aunt over 30 years before. They undertook two days of engagements before retiring to Honselaardijk, which was to be their primary residence. In early January, Mary undertook her first solo duty by receiving the ladies of her husband’s court – it was her moment to adhere to the foreign customs of the rigid Dutch court. Unfortunately, William’s direction dictated that she was only allowed to bestow a kiss of greeting to women of noble birth, not women who had married into nobility – as such, she offended half the group and prompted speculation that she would be just as haughty as William’s mother.

But miraculously, over the next four months William and Mary apparently fell in love. Once the welcome festivities were over, the two were left alone to establish a routine and William, much more comfortable at home than he had been in London, grew to appreciate Mary’s presence in his household and she him. By March, when William left to push back on French military aggression, Mary was pregnant and devastated by his departure. She joined him twice at the end of March and mid-April, but the second journey was onerous and she suffered a miscarriage that left her gravely ill.

William returned in May, but by the summer was gone again, this time his actions resulting in a temporary peace with France in August. Mary was pregnant once more, but she fell ill and rumors spread that she miscarried again. The pregnancy held and in October, Mary Beatrice and Anne came to The Hague to visit, lifting her spirits enormously. The two women stayed for a month, during which time they landed on “Lemon” as a new pet name for Mary. As of February 1679, William was busy preparing for what he believed was the imminent birth of an heir, but by the spring it was clear no child was forthcoming. It’s unclear what exactly went wrong – some speculate the Princess miscarried again, while others suspect her general ill health may have brought about pregnancy-like symptoms akin to what Mary I experienced in the 16th century.

The English political opinion was that it was “made up” thanks to William’s own ambitions to lay claim to the throne. Mary Beatrice, though sympathetic to her stepdaughter, told everyone she was convinced Mary had never been pregnant at all. By then, of course, the Duchess of York had just buried another daughter the year before, and from six pregnancies she only possessed one daughter, Isabel.

As for Mary, whatever she was ill with left her bed-ridden and weak until summer.

Back in England, things weren’t going much better. Out of political hysteria brought on by increasing paranoia over Catholics in government, Charles eventually bid his brother and sister-in-law to move to the continent. They, along with Anne and Isabel, settled in Brussels, though James made a trip to The Hague to share his misery with William and Mary. After learning that Charles was ill, he returned to England in a panic only to find the King recovering from a mild flu. Annoyed, he then insisted that Charles’s bastard son, who some saw as a viable heir to the throne since he was at least Protestant, be exiled as well.

As such, Charles, Duke of Monmouth arrived at The Hague in September 1679 where he received a cold welcome from the Prince and Princess of Orange. William finally offered to host him for a meal, as well as a private audience, during which Monmouth told him that his father would let him return to England soon and hinting he had a viable chance at inheriting. In return, William offered his friendship, but warned him he would withdraw it if Monmouth meant to claim he was legitimate (or rather, that his parents had privately wed). In the end, the young man stayed at the Dutch court for a few days.

The next month, the York family prepared to return to England and James asked Mary to meet him in Delft for a meeting. For half an hour, he shared his grievances with William, while Mary visited with her stepmother and sisters. With the exception of Anne, it would be the last time Mary ever saw her family.

In February 1680, Mary was ill once more, this time grave enough that William wrote to her father telling him to prepare for the worst. Her continued poor health and the fact that she had not conceived in a year changed the dynamic between the spouses and many in Mary’s household began to dislike William for what they believed to be verbal and emotional abuse. In the middle of this, William reportedly took a mistress for the first time in his marriage.

The woman of choice was one of Mary’s English ladies-in-waiting by the name of Elizabeth Villiers. Elizabeth and her two sisters, Anne and Katherine, accompanied Mary to The Hague when she married, though little is known of her relationship with the Princess. Indeed, little is known about her relationship with William, with some arguing that it was never a physical affair, but rather an emotional one. William was fond of his wife, and the theory goes that Elizabeth offered a more rational and even-tempered point of view when William wished to express himself. Indeed, there is evidence that Mary had to be handled carefully as she convalesced and came to terms with the possibility she would never successfully deliver a child.

William traveled to England alone in the summer of 1681 to persuade Charles to prompt financial support in defending the Spanish Netherlands against France. Unfortunately for him, England was too focused on its own domestic drama to pay much attention. William was livid that Charles didn’t understand the threat of French aggression and Charles was annoyed that the Prince couldn’t comprehend how dire the situation with Parliament was. The trip ended poorly with nothing achieved.

Relations between William and Mary with her family continued to sour as the 1680s wore on. James distrusted William’s ambition, assuming he wanted him displaced so that he and Mary could succeed, while Anne’s marriage in 1683 to Prince George of Denmark had nearly included a provision in the contract barring William from the succession. The matter was dropped, but given Denmark’s alliance with France, William never trusted his brother-in-law.

The following year, Monmouth returned to The Hague for a several month stay. Given his rivalry with James, Charles and James were livid with what they saw as William’s disrespect and recklessness, but William was further annoyed that the men thought they could dictate how he handled affairs in his own land. Monmouth stayed and was on such friendly terms with William and Mary – and given such free access – that even the Dutch courtiers were surprised by the break in formality. In truth, William likely never saw Monmouth as a true threat to his own inheritance, with most of the English Protestants viewing Mary as the natural heir.

Finally, on February 6, 1685, Charles passed away following a stroke. He was succeeded by James, who wrote to William:

“I only have time to tell you that it has pleased God Almighty to take out of this world the King my Brother, you will from others have an account of what distemper he died of, and thus all the usual ceremonies were performed this day in proclaiming me King in the City and other parts, I must end which I do with assuring you, you shall find me as kind to you as you can expect.”

Mary, now first in line to the throne, was thus even more important. Isabel had died in 1681 aged only four, while the Duchess suffered through four more pregnancies resulting in stillbirths, a miscarriage and one daughter who lived only two months. From The Hague, it seemed a safe bet there would never be a male heir.

Monmouth, however, was still William and Mary’s guest at the time of his father’s death and he didn’t take the news well. After several days of sobbing, he was advised by William, who had received a letter from James demanding the man’s arrest, that he should prepare to leave for England make his peace with his uncle’s reign or move to central Europe where his safety could be better-protected. Instead, Monmouth became galvanized by the support of the Scots and few staunch Republican leaders in launching his own rebellion. It was at this point where he lost William’s support, for the Prince couldn’t condone a rebellion and Monmouth’s reign would have ousted Mary.

When Monmouth arrived in England his “invasion” was quickly shut down and James had him and his supporters arrested and executed by July 15.

Relations between James and Mary were then noticeably cooler. His favoritism of Anne meant she was given a significantly higher allowance; when Mary asked why there was such a disparity, James responded he couldn’t account for what funds might be used against him in the future. The situation was apparent enough that many suspected James was trying to convinced Anne to convert to Catholicism so as to push Mary out of the succession in favor of her younger sister. Worse, James worked with members of Mary’s household to highlight her husband’s perceived infidelity with Elizabeth Villiers, which worked for a time. She grew cold to her husband, a situation that wasn’t rectified until William intercepted her household’s correspondence, read them and confronted Mary that spies in her employ were doing her a disservice.

Even more sinister was the rumor that James meant to annul his daughter’s marriage and marry her to Louis XIV, whose first wife, Maria Theresa of Spain, died in 1683. Louis was said to have entered a secret union with his favorite mistress, but the legality of that was debatable and easily dissolved in the face of an Anglo-French alliance that would have completely isolated Holland. In light of those machinations, James’s decision to sow discord between the spouses makes sense.

By 1686, James was well on his way to re-establishing Catholicism in England. When Mary broached the subject with Anne, she was relieved when her sister responded that she and George were still adamantly Protestant amidst considerable pressure pressure from their father.

It was around this time that Mary received a Scottish clergyman who asked her what role her husband would have if and when she became queen. Apparently it had never occurred to her that William wouldn’t automatically become king, an ignorance she can be forgiven in light of how Mary I and Elizabeth I treated their own marital statuses. Within a day, Mary told William emphatically she expected him to be named king alongside her – indeed, that would follow the pattern of their marriage. Mary wasn’t political, and though William never sought to include her in the day-to-day governance of his lands, she also never indicated much interest or inclination to do so either.

At the end of 1687, Mary learned that her stepmother was once again pregnant. It was the first time Mary Beatrice had conceived in four years and Mary found her father’s confidence in the matter suspicious, particularly given their track record. As she wrote in her journal, his words were “in a manner so assured and that in a time when no woman could know anything for certain that there was certainly cause enough to raise a small suspicion.”

Meanwhile, gossip floated to the continent that the progression of Mary Beatrice’s pregnancy was faster than normal, while her insistence that she carried a son was disconcerting. Anne wrote to Mary confirming the speculation, noting that she wouldn’t put it past the Catholics at court to have come up with a plot to trick the world into thinking the King and Queen had produced a son via a changeling. Anne further wrote that when Mary Beatrice undressed in her presence, she left the room to put on her smock and that she uncharacteristically slapped Anne with a glove after one too many questions. Relations between the two women permanently soured.

Real or fake, the pregnancy was a crisis for William and Mary. It’s unclear exactly when William decided an invasion would be necessary to secure his wife’s claim, but one strong possibility is March 1688 when he received three Protestant Englishmen, Arthur Herbert and William and Edward Russell, who proposed that William be “invited” to “rescue” England from papists.

On June 10, Mary Beatrice gave birth to a healthy son a month before everyone thought she was due. Only Catholics were invited to witness her lying-in, doing nothing to quell Protestant suspicions. Anne had been out of London taking the waters in Bath, and though she immediately returned to see the child, she wrote to Mary she would never forgive herself for not having stayed to keep a closer eye, herself unsure whether the baby was in fact their half-brother.

And while the whispers may seem mean-spirited, there is some ground for question. The child, baptized James, was the only healthy child that James and Mary Beatrice produced. They would have another daughter four years later who always suffered from poor health and passed away at the age of 19. Only James, the possible changeling, lived to the robust age of 77 in marked contrast to the rest of his father’s children.

On June 30, Arthur Herbert set sail from England for Holland with a formal invitation from the Earls of Devonshire, Danby and Shrewsbury, Richard Lumley, Edward Russell, Henry Sidney and Dr Compton, Bishop of London, asking William to “save” England. For Mary, it was the moment of reckoning as she sorted through her loyalty to her father, who she didn’t trust, and her husband, who was being asked to launch a treasonous rebellion. In the end, of course, her loyalty to William won out, but it was a matter on which Mary grieved and prayed for months.

At the end of July, Mary Beatrice wrote to her:

“Since I have been brought to bed, you have never once in your letters to make taken the least notice of my son, no more than if he had never been born, only in that which Mr Zuylenstein brought, that I look upon as a compliment that you could not avoid, though I should not have taken it so, if ever you had named him afterwards.”

William issued a declaration to the English people on September 30, promising to arrive in England so as to hold a lawful Parliament, prompted by a perceived alliance between James’s government and France, which would be game over for the Dutch politically and economically. On October 9, James wrote to Mary one last time:

“And though I know you are a good wife, and ought to be so, yet for the same reason I must believe you will be still a good daughter to a father that has always loved you so tenderly, and that has ever done the least thing to make you doubt it […] You shall still find me kind to you, if you desire it.”

Mary Beatrice added:

“I don’t believe you could have such a thought against the worst of fathers, much less perform it against the best, that has always been so kind to you, and I believe has loved you better than all the rest of his children.”

Given their behavior over the last few years, their words are ridiculous, but their intended effect of laying on the guilt hit the mark. Even so, Mary remained true to her husband. Before leaving, and prepared for an invasion and all out war against the English, William advised her that if he died in the effort, she must remarry another Protestant.

After several false starts thanks to bad weather, William and his fleet finally left for England on November 11. By the end of the year, James took leave in the darkness of night to flee for the continent, having already sent Mary Beatrice and his young son to France. The invasion was in fact bloodless. As for James, he was effectively allowed to leave by his son-in-law, who was able to sidestep the dirty task of regicide by allowing him the fate of an exile.

Mary joined William in England in the early days of 1689 and they were crowned, jointly and as equals, that spring. We’ll save the details of the Glorious Revolution and their co-rule for another day, but it was the 11 years that William and Mary spent together in The Hague, watching the events in England unfold, which set the tone for how they presented themselves and worked together as king and queen.