Hello Katherine and thank you for your post. Let me first congratulate you on an impressive and extensive work of research into the life and times of Simon de Montfort. I know from my own research into a contemporary of his, Sir Othon de Grandson, just what a labour (of love?) it is and I have only been at it for three years, not thirty! What follows, is a commentary on some aspects of your books, written with no intent of criticism.
There has been much discussion elsewhere on this forum as to how much fiction should/could a work of historical fiction contain. There has been no definitive answer!
I think that you will see from my first post on this thread that I recognise that your books are works of fiction and that therefore you are free to give your own interpretation of his story. Also, contrary to your assumption, I did, of course read the Historical Context section. I do however take issue with some of the statements therein which you use to justify your theory, often in the face of compelling chronological evidence to the contrary. You, for example state as fact that (the fair) Rosamonde was poisoned by Eleanor of Aquitaine. From what I have read, this theatrical murder is thought to be totally untrue and Eleanors supposed words, choose your death, it will be either knife or poison, were only attributed to her in the 17th century.
It is, as you surmise, the very contentious notion that Simon and Queen Eleanor were lovers and that Simon fathered the future King Edward 1, with which I take most issue. There is nothing wrong, I guess, with introducing such a theory in a work of fiction and it certainly spices up some aspects of your work. The use of such fiction is certainly not forbidden as you query in your post. However, if one truly want to explore a plausible sequence of cause and effect (as stated in your Acknowledgements), in a work of historical fiction, it seems to me that one should adhere as much as possible to the established and accepted chronology of events, unless one has alternative sources which factually contradict them.
You have it that Eleanor was already pregnant when her marriage to Simon took place in Jan 1238 and that the baby was born in August. The king and queen then visited Kenilworth in September and that is where the adulteress liaison between Simon and the queen took place, resulting in the birth of Edward 1 in June the following year. This sequence of events appears to be loosely based on a statement in Magaret Labarges book on Simon (which I have not read) which you have accepted as true despite her not providing any source for her statement, together with some missing evidence of the kings whereabouts from the records for September 1238.
Matthew Paris, provides first hand evidence contrary to the above in his statement that "On St. Calixtus's day (Oct 14 1238),Simon de Montfort returned to England and was received by the king and all the royalists to the kiss of peace. He then set out with all haste to his wife Eleanor, who was staying at Kenilworth, very near her confinement." Matthew Paris then relates that Simon's son Henry was born in Advent on the 28th November 1238.
On your web page in a part answer to one query you stated: I know many historians frown on the reliability of the monks' reportage, but Brother Matthew, who kept the Chronica, had first hand access to eyewitnesses, including Montfort himself. I'm willing to believe him. Why, if you believe Matthews chronicle and he was almost certainly writing verbatim, do you differ from his record of the birth of Simon and his wifes eldest son? This son, by the way, was given the name of Henry in honour of the king.
Henrys turning against his sister and Simon is also faithfully recorded by Paris and in Simons own words (see Bemont p.60-61). Henry was always beset by financial problems and Simons unauthorised citing of him as security for his debts to Thomas of Flanders, together with the poisonous words of Archbishop Rich on Simons seduction of Eleanor before their marriage and his alleged bribing of the Roman Court to obtain the lifting of Eleanors vows of chastity, would have been enough to have him sent from court. Later of course he relented and subsequently made Simon his Viceroy in Gascony, hardly the actions of someone who believed that Simon had seduced the queen. If he truly had believed that of Simon, I do not believe that he would ever have forgiven him (or his queen?),
It is clear from his many actions that Henry loved Edward, named him as his heir (not his brother Edmund) and, in spite of a few father/son clashes, provided him with an enormous appanage upon his marriage in 1254. Several chroniclers and some eminent historians also mention that Edward had inherited his fathers drooping eyelid!
That Edward felt the same about Henry is evidenced by the fact that when Henry died (at about the same time as Edwards son John) Edward was returning from Sicily and Charles of Anjou, with whom he was staying, noted that Edward seemed unconcerned about his son, but was extremely upset about his father. He explained that it was easy to beget sons, but the loss of a father was irredeemable!
Finally (at least for the moment!), no apologies from you are necessary. I do not believe that you have offended anyone, nor that your purposes have been salacious. I have read the first two books and I intend to read the whole series, with as much an open mind as possible. I look forward to how you treat Edward falling under the influence of Simon, their subsequent estrangement and the barons war that follows!