Though she had born him several children, they all died in early infancy, except one daughter, and he was the more struck with this misfortune, because the curse of being childless is the very threatening contained in the Mosaical law against those who espouse their brother's widow.

The succession, too, of the crown was a consideration that occurred to every one, whenever the lawfulness of Henry's marriage was called in question; and it was apprehended, that if doubts of Mary's legitimacy concurred with the weakness of her sex, the king of Scots, the next heir, would advance his pretensions, and might throw the kingdom into confusion.

The evils, as yet recent, of civil wars and convulsions arising from a disputed title, made great impression on the minds of men, and rendered the people universally desirous of any event which might obviate so irreparable a calamity.

And the king was thus impelled, both by his private passions and by motives of public interest, to seek the dissolution of his inauspicious, and, as it was esteemed, unlawful marriage with Catharine.
Henry afterwards affirmed that his scruples arose entirely from private reflection; and that on consulting his confessor, the bishop of Lincoln, he found the prelate possessed with the same doubts and difficulties.
The king himself, being so great a casuist and divine, next proceeded to examine the question more carefully by his own learning and study; and having had recourse to Thomas of Aquine, he observed that this celebrated doctor, whose authority was great in the church, and absolute with him, had treated of that very case, and had expressly declared against the lawfulness of such marriages.[*] * Burnet.

Fiddes.
The prohibitions, said Thomas, contained in Leviticus, and among the rest that of marrying a brother's widow, are moral, eternal, and founded on a divine sanction; and though the pope may dispense with the rules of the church, the laws of God cannot be set aside by any authority less than that which enacted them.