The idea of "star-crossed lovers" whereby two young people fall in love, even though their families do not get along, is a common part of life in society. The idea of it was set to the Greek tragedy "Pyramus and Thisbe." Ovid's is the oldest surviving version of the story, published in 8 AD.

More popular versions came into existence with the first production of "Romeo and Juliet" by William Shakespeare in 1597. Continuing that story in more modern times is the basis of the popular Broadway hit, "West Side Story" in 1957.

In each of these stories, two innocent youngsters, aware of their differences, settle on their similarities instead. They choose to ignore the historical familial and cultural differences to continue their lives in the best way they know. Of course, they do not exist alone in the world, and others plot to keep their happiness away. The tragedy unfolds in complicated ways until both of the lovers are dead, not understanding why the other had died.

More Info: en.wikipedia.org