Tsaria is quite right. Jane Grey and her husband Guilford Dudley were entirely the pawns of their respective parents; in his case, his father, the Duke of Northumberland and in hers, that of her mother Frances Duchess of Suffolk, granddaughter of Henry VII.
It is believed that Jane's adherence to the Protestant religion was sincere and that she did subscribe to the idea that her claim was legitimate in view of Mary's Catholicism.
Mary's decision to impose the ultimate penalty upon Jane was not, I am sure, made lightly. If anyone should have been punished severely, it should have been the Duchess, as her dynastic aspirations and hunger for power were just as voracious and disastrous as those of Northumberland.
Interestingly, the Dudleys were to have more success in the later reign of Elizabeth, as Robert Dudley, who shared Mary's displeasure and disaffection became close to the young Princess Elizabeth during their respective sojourns in the Tower. He was created Earl of Leicester by her and was the chief favourite at court until his death; it is rumoured by some that they were lovers and he had been widely tipped to become the Queen's husband, which would have satsified all his late father's dynastic hopes; only the scandal surrounding the death of his wife Amy Robsart putting paid to his royal matrimonial prospects. What is certain is that he is the only man that she ever truly loved........