By the end of the 1630s, relations between the various factions in English society had become very tense; controversies over religion, social relations, morality, and political power became more and more heated.
At the same time, Mary's mother, who openly professed Catholicism, became more and more unpopular in the country.
In late 1640–early 1641, King Charles I decided on renew negotiations with Prince Frederick Henry of Orange.

The negociations progressed quickly and already on 10 February 1641 King Charles I announced to the Parliament that the agreement on the marriage of his daughter was actually concluded and that it only remained to consider this union from a political point of view.
The English sovereign himself hoped that in case of emergency, the Prince of Orange would help him to maintain royal power in England.
A modest wedding ceremony took place on 2 May 1641 at the Chapel Royal in Whitehall Palace, London.
Queen Henrietta Maria was unable to attend the religious ceremony as it was a Protestant one; instead, she watched her daughter's wedding from a small gallery.
The marriage of the King's eldest daughter was practically not celebrated in England, as the country was on the verge of a war that broke out in less than a year.
Mary and William received congratulations from the courtiers, as well as several gifts; in addition, in honor of the newlyweds, a volley of 120 guns was fired, after which William returned to the Netherlands.
According to the marriage contract, Mary could remain in England until she was 12-years-old; her husband had to provide her with 1,500 livres per year for personal expenses, in addition, in the event of the untimely death of William, Mary received a maintenance of 10,000 livres per year and two residences for her personal use.
The marriage contract also contained a clause according to which Mary and her courtiers were allowed to freely practice their religion, which was somewhat different from the religion in the country of her husband.

In early 1642, the situation in the country heated up.
Mary and her parents were forced to take refuge in Hampton Court, but the situation steadily turned into open war, and in February Queen Henrietta Maria departed with her daughter to The Hague; in order to ferry the princess and her mother to the Netherlands in England, a Dutch escort of fifteen ships arrived.
With Mary in the Netherlands went to her governess, Lady Stanhope, which later became a confidant and companion of the princess.
From a political point of view, the marriage of Mary partially paid off in 1643, when Queen Henrietta Maria was able to convince the Dutch government to provide her husband a ship arms and cross over with them in Yorkshire.

Shortly before leaving for the Netherlands, Mary was designated by her father Princess Royal, thus establishing the tradition that the eldest daughter of the British sovereign might bear this title.
The title came into being when Queen Henrietta Maria, the daughter of King Henry IV of France wished to imitate the way the eldest daughter of the French king was styled (Madame Royale).
Until that time, the eldest daughters of English and Scottish kings were variously titled lady or princess (The younger daughters of British sovereigns were not consistently titled princesses of Great Britain and styled Royal Highness until the accession of George I in 1714).

In November 1643, the second marriage ceremony between Mary and William took place in The Hague.
Despite the fact that Mary was already 12-years-old, her marriage wasn't consummated until 1644.
In February 1644, Mary completely merged into the life of the Dutch court.
She gave audiences, met with foreign ambassadors and performed all the functions assigned to her with an importance and dignity astonishing for her age.
In March, she participated in a number of court celebrations on the occasion of the recent alliance between France and the Netherlands and led by entertainment that her husband arranged for the French ambassador.

Mary, who constantly receiving news from England, sympathized with
By the end of the 1630s, relations between the various factions in English society had become very tense; controversies over religion, social relations, morality, and political power became more and more heated. At the same time, Mary's mother, who openly professed Catholicism, became more and more unpopular in the country. In late 1640–early 1641, King Charles I decided on renew negotiations with Prince Frederick Henry of Orange.
The negociations progressed quickly and already on 10 February 1641 King Charles I announced to the Parliament that the agreement on the marriage of his daughter was actually concluded and that it only remained to consider this union from a political point of view. The English sovereign himself hoped that in case of emergency, the Prince of Orange would help him to maintain royal power in England. A modest wedding ceremony took place on 2 May 1641 at the Chapel Royal in Whitehall Palace, London. Queen Henrietta Maria was unable to attend the religious ceremony as it was a Protestant one; instead, she watched her daughter's wedding from a small gallery. The marriage of the King's eldest daughter was practically not celebrated in England, as the country was on the verge of a war that broke out in less than a year. Mary and William received congratulations from the courtiers, as well as several gifts; in addition, in honor of the newlyweds, a volley of 120 guns was fired, after which William returned to the Netherlands. According to the marriage contract, Mary could remain in England until she was 12-years-old; her husband had to provide her with 1,500 livres per year for personal expenses, in addition, in the event of the untimely death of William, Mary received a maintenance of 10,000 livres per year and two residences for her personal use. The marriage contract also contained a clause according to which Mary and her courtiers were allowed to freely practice their religion, which was somewhat different from the religion in the country of her husband.
In early 1642, the situation in the country heated up. Mary and her parents were forced to take refuge in Hampton Court, but the situation steadily turned into open war, and in February Queen Henrietta Maria departed with her daughter to The Hague; in order to ferry the princess and her mother to the Netherlands in England, a Dutch escort of fifteen ships arrived. With Mary in the Netherlands went to her governess, Lady Stanhope, which later became a confidant and companion of the princess. From a political point of view, the marriage of Mary partially paid off in 1643, when Queen Henrietta Maria was able to convince the Dutch government to provide her husband a ship arms and cross over with them in Yorkshire.
Shortly before leaving for the Netherlands, Mary was designated by her father Princess Royal, thus establishing the tradition that the eldest daughter of the British sovereign might bear this title. The title came into being when Queen Henrietta Maria, the daughter of King Henry IV of France wished to imitate the way the eldest daughter of the French king was styled (Madame Royale). Until that time, the eldest daughters of English and Scottish kings were variously titled lady or princess (The younger daughters of British sovereigns were not consistently titled princesses of Great Britain and styled Royal Highness until the accession of George I in 1714).
In November 1643, the second marriage ceremony between Mary and William took place in The Hague. Despite the fact that Mary was already 12-years-old, her marriage wasn't consummated until 1644. In February 1644, Mary completely merged into the life of the Dutch court. She gave audiences, met with foreign ambassadors and performed all the functions assigned to her with an importance and dignity astonishing for her age. In March, she participated in a number of court celebrations on the occasion of the recent alliance between France and the Netherlands and led by entertainment that her husband arranged for the French ambassador.
Mary, who constantly receiving news from England, sympathized with 
Mary, Princess Royal and Princess of Orange