I dont think anyone is denying he was a usurper, but there were many before him and many after him. James II was run out of England and replaces with his own daughter. There are still people who believe the Stuarts are the rightful royals in England not the Windsors.How much claim did Henry Tudor have in comparison to Sophia of Hanover?
Sophia of Hanover had solid claims as a granddaughter of James I and VI of England and Scotland:
James I and VI of England and Scotland -> Elizabeth Stuart -> Sophia, Electress of Hanover.
When the Parliament decreed no Catholic should ever ascend to the Throne, her claims became the strongest. The Parliament didn't select a random person from a royal bloodline - they selected the person highest in the line of succession (based on rules of primogeniture). Now, Sophia actually had 11 elder siblings, most of them alive at the time of the 1701 Act. However, all of them were "unfit" in the eyes of the Parliament because they were either Catholics themselves, or married to ones.
Henry Tudor had
no claims whatsoever, apart from his right to the Crown by Conquest.
On his father's side (Edmund Tudor, 1st Earl of Richmond), he was descended from French Monarchs. Namely, his grandmother Catherine of Valois was the daughter of Charles VI of France. His grandfather, Owen Tudor, was a common soldier whom Catherine may have married.
On his mother's side (Lady Margaret Beaufort), he was indeed descended from English Kings - but through an
illegitimate line. Lady Margaret was male-line great-granddaughter of John of Gaunt - Edward III's third surviving son. Her grandfather was John Beaufort, 1st Earl of Somerset - one of the children John of Gaunt had with his mistress, Katherine Swynford. John subsequently married Katherine and those children were legitimised by an Act of Parliament. However, another Act specifically
barred those children and their descendants from having any claims to the Throne. Henry's line through Margaret was the following:
Edward III -> John of Gaunt -> John Beaufort -> John Beaufort, 1st Duke of Somerset -> Lady Margaret Beaufort -> Henry Tudor
Now, even assuming the succession rights of the children of John of Gaunt and Katherine Swynford were reinstated, there were still plenty of other people with better claims, among them,
George Grey, 2nd Earl of Kent. George Grey was also a descendant of John of Gaunt (through legitimate line) through his father:
John of Gaunt -> Elizabeth of Lancaster -> Lady Constance Holland -> Edmund Grey, 1st Earl of Kent -> George Grey, 2nd Earl of Kent
He was also descended from John of Gaunt through is mother (through the same illegitimate Beaufort line):
John of Gaunt -> Lady Joan Beaufort -> Lady Eleanor Neville -> Lady Katherine Percy -> George Grey, 2nd Earl of Kent
He was also descended from Edward III's
second son, Lionel of Antwerp, 1st Duke of Clarence, thus giving him superior claims:
Edward III -> Lionel of Antwerp -> Philippa Plantagenet -> Lady Elizabeth Mortimer -> Henry Percy -> Lady Katherine Percy -> George Grey, 2nd Earl of Kent
The point is, Henry Tudor was as much an usurper as William the Conqueror - someone who claimed the Throne with absolutely no rights to it. Even his troops consisted of foreign mercenaries and not, contrary to the popular myth, of Englishmen tired of Richard's "tyranny". Richard, whom (non-biased, contemporary) historians called the only gentleman on the field, would have won had it not been for the treachery of the Stanley brothers – his one time allies (then again, one of the brothers was married to Lady Margaret Beaufort, so had Richard not been so lenient, he would have foreseen the course of events).
Richard III usurped his nephew and whenever they died Elizabeth of York could be argued to have been Queen of England in her own right not her uncle.
The usurpation bit is pretty much a myth that arose during the Tudor Era (most notably, in Shakespeare's play). The boys were born during the lifetime of the lady Edward IV had promised to marry (which equalled actual marriage contract at the time) before marrying Elizabeth Woodville, making them illegitimate. But that was not the main problem: remember how the situation was in England at the time - the country was just recovering from the War of Roses, old wound were just starting to heal. Under the circumstances, no one wanted another boy King to reign because some of England's worst pages of history (including the War of Roses) happened because of reigns of under-age Kings and their Regents. Moreover, the reign of Edward V would inevitably mean the Woodvilles behind the Throne - and one thing both Yorks and Lancasters were united in was hatred towards most members of the family (and, given their conduct, that's hardly surprising).
Richard of York was
offered the Throne - not usurped it. He was considered a just and wise ruler; he was quite loved and respected - a perfect candidate for Kingship. The myths of evil King Richard appeared because of a highly successful Tudor propaganda, but are not supported by any contemporary facts.
I have yet to to see any explanation on how Henry Tudor could have killed Edward and Richard when be was not in the country when they disappeared. Who could he have written to and given the task to kill them? How powerful were his alliances in England that he could have taken part in such conspiracy. He may have had as much reason to want then out of the way, but he doesn't seem to have had the means or access.
The young Princes were last seen in 1483 - and Henry Tudor was indeed not at the country at the time. However, hiring someone to kill the Princes would not have been very difficult at all. I suggest you to read about
Henry Stafford, Duke of Buckingham - a one-time ally of Richard's who deserted his side to join Henry Tudor; coincidentally, it happened at approximately the same time the boys were last seen.
Not to mention, Margaret Beaufort - who was very much in England at the time - could have hired someone herself. It is not as far-fetched as it sounds because Margaret was a very wilful person who usually got what she wanted - and she wanted her son to be King.
Elizabeth of York was the Yorkist heiress and would have been heiress to the Throne if there were no questions of her legitimacy. However, a woman on the Throne was, at the time, undesirable for much the same reasons as a boy King; the only previous female claim (Empress Matilda’s) resulted in a bloody and lengthy Civil War.
I’m not stating it as a fact Richard III is innocent – although personally I believe that to be the case. He could have killed his nephews, but such violent actions were very much against his character. It was, however, very much in Henry Tudor’s character, who executed pretty much every claimant immediately after his accession to the Throne, regardless of their age, status or guilt (or lack of it).
