The Tudors is the show that focuses heavily on Henry VIII's biography and personal relations - however, one of the closest people in Henry's life withstood major changes from her historical counterpart. What is portrayed as Princess Margaret in the series is actually a combination of Henry's two sisters - Margaret, Queen of Scotland, and Mary, Queen of France.
The fictional Princess Margaret (Gabrielle Anwar) was the only sister of Henry VIII - a feisty woman who dares to argue with her brother and is ruled by her heart, rather than her head. In the tv series, she is forced to marry the elderly king of Portugal, whom she kills shortly after the wedding - and marries Charles Brandon, one of Henry's closest friends, without his permission. After some time in exile with her new husband she gets sick and dies.
Princess Margaret in the series is very, very similar to her historical counterpart princess Mary Tudor. She was the sister married off to an elderly king, although not of Portugal, and she was the one who seduced Charles Brandon into marrying her despite her brother's wishes, right after her royal husband was dead less than a year passing since their wedding.
The real princess Mary
Princess Mary Tudor was the fourth and youngest surviving child of Henry VII and Elizabeth of York - and growing up was considered one of the most beautiful princesses in Europe. She received her first marriage proposal at the age of 2, then at the age of 4 she was offered to marry the future Holy Roman Emperor Charles - that proposal was on hold for some time and then revived again. Up until Spain allied with France the year Mary was supposed to marry Charles - and her brother Henry VIII has to negotiate and strike the best deal for England through his beautiful young sister.
Less than a month after Mary renounced her marriage to Charles, she married king Louis XII of France by proxy - the man 34 years her senior. Although Mary didn't have much say in the matter, it is said that she made Henry promise that after her husband's death she will marry the man of her choosing.
Mary didn't have to wait too long - her marriage lasted only 82 days, as Louis XII died on New Year's Eve, and so the Tudor princess was free to be remarried. Charles Brandon, duke of Suffolk and Henry VIII's closest friend from childhood, was sent to France to take care of financial negotiations and to bring the princess back home. Henry specifically instructed Brandon that he kept his relationship with Mary to strictly business.
However, after 40 days of seclusion and doubting that her brother will honour his word regarding her next marriage, Mary persuaded the handsome, charismatic Charles Brandon to marry her without Henry's permission. Which he did.
Charles Brandon was not a royal duke, however, - in fact, he was considered a much lower-born man who raised to his friendship through personal affection and friendship with Henry. Therefore, marrying a royal princess without the king's permission caused a scandal and Henry's rage. After careful negotiations, begging and correspondence between the couple and Henry, he finally forgave them - and made them pay dearly for their disloyalty. After paying off the expenses for all the travelling, Mary's first dowry and Brandon giving up wardship of Elizabeth Grey, they returned to England and married for the second time, this time with Henry's blessing.
Since then Mary lived in the country and only occasionally appeared at court, primarily for important events and weddings. She was known to oppose Henry's marriage to Anne Boleyn and supported his first wife Katherine of Aragon. Her health started to deteriorate four years into marriage but she lived on until the age of 38 - it is still unknown from what kind of disease.
Is princess Margaret from The Tudors similar to Mary Tudor?
The two are incredibly similar - the show's princess Margaret follows Mary's biography pretty closely, while the real Margaret Tudor's influence on the character is almost non-existent. Similarly to Mary, Margaret didn't want to be married off to an elderly king and started to develop a passion for Charles Brandon early on. She was exiled from court for defying her brother - although not in France, but in the countryside in England. In the show, she also dislikes Anne Boleyn and dies of an unknown disease when she's still young.
Mary Tudor – The rose among the lilies of France, History of Royal Women
Mary Tudor - Romantic Rebel, Scandalous Women
A Tudor Romance: Mary Tudor and Charles Brandon, History in an Hour
Mary Tudor, English Monarchs
Death of Mary Tudor, Queen of France, The Anne Boleyn Files