But first, some history: In 1520, King Henry VIII attended the wedding of almost 12 year old Mary Boleyn and William Carey. According to "Henry VIII: The King and His Court" by Alison Weir, "At some stage, perhaps even before her marriage, although the timing is not clear, Mary Boleyn became the King's mistress, supplanting Elizabeth Blount in his affections."

In 1526, Mary gave birth to her second child, a son called Henry. He was widely considered to be the king's son. He physically resembled the king, a fact often remarked upon. Perhaps more telling, Henry granted the Careys manors and estates during the affair and immediately before the child's birth.

The King, who had already acknowledged one illegitimate son, did not do so with Henry Carey since by that time he was determined to divorce Katharine of Aragon and marry Anne Boleyn, the child's aunt. Henry VIII would have been too embarrassed to recognize his bastard son by his fiancée's younger, married sister who had already given him a daughter.

The conclusion by historians is that Mary and William's two children were the king's children. This suggests to historians that the marriage of William and Mary Carey was Platonic. Henry Vlll was obsessed with one thing - producing a legitimate male heir. Imagine the stress this put on his wives!

Princess Diana famously remarked that she had done her duty for her country and her sole purpose in life - producing not only an heir, but a spare as well.

"The Other Boleyn Girl" tackles the intense jealousy and conflicts that went on between Anne (Natalie Portman) and her younger sister, the virginal, saintly Mary (Scarlett Johansson), for the affection of King Henry (Eric Bana).

Anne and Mary's father, Thomas Boleyn (Mark Rylance), is ruled by his brother-in-law the Duke of Norfolk (David Morrissey), who plots to put Anne in Henry's path after finding out that the King has lost sexual interest in his wife, Katharine of Aragon (Ana Torrent). Soon the King will be looking for a mistress, and the Boleyn family would profit handsomely if Anne were chosen. The girls' mother, Lady Elizabeth (Kristin Scott Thomas), is horrified that her daughters are being prostituted.

Willingly, Anne is presented to Henry, but when he sees sweet, blond, naïve Mary, he is enchanted. He appoints Mary as one of Queen Katharine's Ladies-In-Waiting and gives a prestigious position at Court to her husband. William Carey (Benedict Cumberbatch) is well aware he is being a cuckold but for some reason not given, accepts. The entire family, including Mary's brother George (Jim Sturgess), is ensconced in London at Henry's Court.

While Mary risks a dangerous pregnancy and is confined to her bed, the Duke of Norfolk tells Anne it is now up to her to seduce Henry. The rest, as they say, is history.

The screenplay by Peter Morgan is based on the 2002 novel by Philippa Gregory. By writing a novel, Gregory posits a few points that have gone unrecorded by historical fact. Her reason, nicely revealed by Morgan, why incest was one of the charges against Anne, is understandable.

I'm not a fan of Portman, but as Anne Boleyn she shows the ruthlessness and jealousy that must have eaten at Anne. Her sister had given Henry a much desired and healthy son. Johansson has the more difficult role - that of innocent sister in the whirl of intrigue and treachery. But the historical Mary produced two children for the King: She must have been quite a sexual rival and was a powerful force at the King's Court.

Bana is big and sexy, but since Henry had been king since he was eighteen he was well accustomed to absolute rule and the indulgence of his every whim. Bana lacks the maniacal egomania that Johnathan Rhys-Meyers has given his portrayal of Henry in The Tudors.