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In his mid-thirties, Henry was in the prime of life and an impressive figure. He was used to having his way with women, not only because he was king, but because he was a strong, charismatic, good-looking man. Encountering one who wouldn't leap into bed with him must have astonished him -- and frustrated him.
Exactly how his relationship with Anne Boleyn reached the point of "marry me or forget it" is not perfectly clear, but at some point Henry determined to repudiate the wife who had failed to give him an heir and make Anne his queen. He may even have considered setting Catherine aside earlier, when the tragic loss of each of his children, save Mary, reminded him that the survival of the Tudor dynasty was not assured.
Even before Anne entered the picture, Henry had been extremely concerned about producing a male heir. His father had impressed upon him the significance of securing the succession, and he knew his history. The last time the heir to the throne had been female (Matilda, daughter of Henry I), the result had been civil war.
And there was another concern. There was a chance that Henry's marriage to Catherine was against God's law.
While Catherine was young and healthy and likely to bear a son, Henry had looked to this biblical text:
"When brethren dwell together, and one of them dieth without children, the wife of the deceased shall not marry to another; but his brother shall take her, and raise up seed for his brother." (Deuteronomy xxv, 5.)
According to this specific charge, Henry did the right thing by marrying Catherine; he had followed biblical law. But now a different text concerned him:
"If a man shall take his brother's wife, it is an impurity: he hath uncovered his brother's nakedness; they shall be childless." (Leviticus xx, 21.)
Of course, it suited the king to favor Leviticus over Deuteronomy. So he convinced himself that the early deaths of his children were signs that his marriage to Catherine had been a sin, and that as long as he stayed married to her, they were living in sin. Henry took his duties as a good Christian seriously, and he took the survival of the Tudor line just as seriously. He was certain that it was only right and just that he receive an annulment from Catherine as soon as possible.
Surely the pope would grant this request to a good son of the Church?
Next: Pope Clement VII