Joseph Campbell, the famous mythologist, traced the history of love through myths and stories from cultures around the world and throughout history. He came up with a shocking thesis: romantic love, as we understand it today, was invented in the 12th century, by the Troubadours in France.
The ancient conceptions of love are familiar: eros is the physical love that underlies romantic love, and cultures around the world celebrated it or sanctioned it in various ways. Agape is the moral form of love, in which you love your neighbor and help people. But the modern form of romantic love did not exist in ancient times.
Marriage, of course, had existed, but it was generally arranged. Various societies had various degrees of formality about how they arranged their marriages, but the marriage was a product of the society's wishes. Campbell emphasizes that many of these arranged marriages had loyalty and fulfillment, but they were different.
The Troubadours celebrated individual choice, that people were free to fall in love with who they wanted. The love stories that the Troubadours told feature lovers struck like lightning with passion, and choosing each other despite the disapproval of their parents, even to the point of accepting death.
Campbell points out an important theme in most of these stories of romantic love: rebellion. Romantic love was a rebellion against the established order. The word, amor, used to designate this love is an inverse of Roma, or Rome: all that represented authority.
Happy Valentine's Day, rebels.