According to Deuteronomy, if a married man dies childless, his brother is obligated to marry the widow—in a union otherwise forbidden. This practice, known as levirate marriage, is the subject of the talmudic tractate Yevamot. (Deuteronomy also prescribes a ritual that can relieve the brother of the obligation.)
Skip forward to 16th-century England. Anxious to obtain a divorce from Catherine of Aragon, previously married to his brother, so that he could marry Ann Boleyn, Henry VIII sought help in an appeal to the finer points of talmudic law. To this end, he ordered a copy of the Bomberg Talmud, the first-ever printed edition, hoping scholars could find an applicable loophole. That was his mistake, as Jeremy Brown writes:
Henry argued that his marriage to Catherine should be dissolved since it was biblically forbidden for a man to marry his sister-in-law. But as we [learn] from tractate Yevamot, the Bible commands a man to marry his widowed sister-in-law if his brother died without children. Since [his brother] Arthur died childless, it could be argued that Henry was now fulfilling the biblical requirement of levirate marriage. . . . If that was the case, the marriage was kosher and could not be dissolved. . . .
[I]t’s a little bit more complicated than that. Behind the scenes were Christian scholars who struggled to reconcile the injunction against a man marrying his sister-in-law, found in one part of the Bible, with the command to do so under specific circumstances, found in another. In fact, the legality of Henry’s marriage [to Catherine] had been in doubt for many years, which is why Henry had obtained the Pope’s special permission to marry.
The bishop of London eventually concocted an argument for nullifying the marriage to Catherine that involved not an appeal to the Talmud but a rejection of papal authority, setting into motion the English Reformation. And now skip forward to the 1950s, when a copy of the Bomberg Talmud was discovered in Westminster Abbey; whether it was the one ordered by Henry VIII remains a subject of debate.
Read more on Seforim: http://seforim.blogspot.com/2015/01/the-greatest-story-in-annals-of-jewish.html