Margaret Beaufort died in 1509. She was a major player in the Wars of the Roses, the swirling on-again-off-again civil wars that consumed England from 1455-1487. Romeo and Juliet was written and first performed in the early 1590s. Your average English person of Shakespeareās day would probably have had at least a vague understanding of who she was and what happened to her, because she was a key figure in recent history and was still getting passed around as a cautionary tale.
There are two great problems with what happened to Margaret (and that her parents are trying to do to Juliet). One is easy for modern people to spot (but was also a common response back in her own day). And thatās the moral implications of what was done to her. She was too young to be married, and it was horrifying that she was forced into it so young. Every one of the adults around her either acted immorally or failed to protect her. They were wrong. This is what modern people see, and itās important to remember that people back in her day mostly agreed with it. Youāre supposed to think itās fucked up! When girls were married that young (and it didnāt happen often!) it was a formality 99% of the time. It was for dynastic or financial reasons (the girl has lots of money and/or land and/or a title that her husband wants), but the ācoupleā donāt consummate their marriage for years. And itās not just that they would have separate bedrooms. They might not even live in the same country until the girl was in her late teens and physically and mentally mature enough to bear and raise kids. Hell, a lot of times they didnāt even meet until the girl was older! They had this thing called āproxy marriageā where you would have two separate ceremonies, in two separate places, with each party saying their vows separately, one in one city and the other in a different one. So, yeah, sure, the girl was technically married at 12, but she didnāt actually meet her āhusbandā in person until she was 17 and they didnāt start sleeping together until she was 20. That was a thing they did.
The other problem, the one that modern people donāt notice, is dynastic. See, marriage wasnāt generally because you loved someone. It was because you had the resources to support a family, and you or your family wanted to pool those resources with someone. Itās about āour family has these resources, and we want that to continue.ā Itās about continuity across generations. Itās about making sure that your children and grandchildren have the best possible resources to survive and thrive, whether those resources are land or a trade or a title or money or whatever. In order for this to work, you have to have kids! The family and the familyās resources depend on the married couple having children. If the couple doesnāt have children, the marriage is a failure. And that failure affects not only the couple, but both families. This is a really big problem. And you canāt have just one kid to pass on the family name, because half of all kids die in early childhood. If you want to be safe, you need several kids, to be sure at least one will survive to adulthood (when they can marry and pass on the family name and resources.
You know what happens when a girl has her first pregnancy too young? She is very likely to either die in childbirth, or have complications that destroy her future fertility. Just like Margaret Beaufort. Just like Julietās mother. In other words, the marriage is a failure, not just for her, but also for her family, and her husband (who canāt divorce her, itās not allowed except in extremely rare circumstances), and her husbandās family. So even the people who didnāt have a moral problem with adult men having sex with pubescent girls had a practical problem with girls married too young because you are very likely to destroy the entire purpose of the marriage by doing it. As Shakespeare reminds us in the play through Julietās mother having been married too young and only having one child.
Shakespeare is telling us āyeah, this is fucked up. but even if youāre the kind of awful person who doesnāt think girls marrying too young is morally wrong, itās also a problem for practical and dynastic reasons, donāt forget that by doing this wrong thing you are very likely to destroy what you most want out of it.ā