Shankar Vedantam

So she started an affair with Julius Caesar, the ruler of Rome.

Cleopatra became pregnant.

When the baby was born, he was named Caesarian.

The child gave Cleopatra and Caesar a claim to each other's throne.

It was something they both desperately wanted.

Sounds like an episode of Game of Thrones, right?

This marriage strategy wasn't just for kings and queens.

There's a common misconception that people of lower classes in this time married for love.

Not true, Stephanie says.

You couldn't run a farm with one person.

You couldn't run a bakery with one person.

If you were a peasant, you wanted somebody who had a good reputation as a hard worker.

A different idea started to become more common in the 1700s and 1800s.

Jane Austen, the famous novelist, may well have been the trailblazer.

For those who don't remember the plot of her book, Pride and Prejudice, Mr. Darcy, who has been promised in marriage to his wealthy cousin, falls instead for Elizabeth Bennet, a woman of modest means.

That throws his aunt into a rage.

So, Stephanie, talk about this.

This is the first glimmers, if you will, of the idea that in some ways love was coming to conquer marriage.

By the second half of the 19th century, the Jane Austen model of marriage had taken firm hold in the United States.

The idea of marrying for anything other than love came to be seen as old-fashioned.