The earliest reference we can find for the phrase “star-crossed lovers” traces it to 1595, attributing it to Shakespeare’s Romeo and Juliet, a tragedy about the doomed romance that blossoms between a young man and a young woman on the brawling streets of Verona, a romance that is destined to fail because the families they come from are locked in a deadly feud: “From forth the fatal loins of these two foes, / a pair of star-cross’d lovers take their life.”

It’s an astrological phrase, of course, stemming from the old belief (still held today by millions of people, as a look at any newspaper will tell you) that the position of the stars at your birth casts a supernatural influence that determines your fate. So to say that a romantic relationship is “star-crossed” is to say that the influence of the stars are working against it, that it’s opposed by fate, ill-fated, “thwarted by a malign star.” Not meant to be. That you’re destined to be kept apart no matter how hard you struggle to be together.

In real life, even without the influence of the stars or the dread hand of Fate, there are any number of things that can doom a relationship—differences in temperament, race, religion, social status, political affiliations, being on different sides of a bitter war, philosophical dogma, degrees of affluence (or lack of it). Even simple distance can work to keep people apart, and over the centuries there must have been many lovers who stood on the dock and watched their loved ones sail off to destinations like Australia or America thousands of miles away, knowing that they’d never see them again, since in the days before modern transportation, they might as well have been sailing off to Mars. Many, many immigrants must have left someone behind them in the Old Country, as they were forced into exile or set off to find their fortunes, and most were never reunited.