Diagram shows how the perception of marriage in the West changed over the centuries and in relation to romance, love and sex. Pre-17th century marriage was an economic and political contract negotiated between families. Love happened outside of marriage. This changed over time. From the 17th to 19th century love was arranged but expected to be a starting point for romance and love. Later, romance lead to marriage and then love. And since the 1960s a progression from sex to romance, then love and only then marriage seems to be the prominent model.