Love
It seems to us natural that love should be the commonest theme of serious imaginative literature: but a glance at classical antiquity or at the Dark Ages at once shows us that what we took for “nature” is really a special state of affairs, which will probably have an end, and which certainly had a beginning in eleventh-century Provence. It seems — or it seemed to us lately — a natural thing that love (under certain conditions) should be regarded as a noble and ennobling passion: it is only if we imagine ourselves trying to explain this doctrine to Aristotle, Virgil, St Paul, or the author of Beowulf, that we become aware how far from natural it is. Even our code of etiquette, with its rule that women always have precedence, is a legacy from courtly love, and is felt to be far from natural in modern Japan or India.
Many of the features of this sentiment, as it was known to the Troubadours, have indeed disappeared; but this must not blind us to the fact that the most momentous and the most revolutionary elements in it have made the background of European literature for eight hundred years. French poets, in the eleventh century, discovered or invented, or were the first to express, that romantic species of passion which English poets were still writing about in the nineteenth. They effected a change which has left no corner of our ethics, our imagination, or our daily life untouched, and they erected impassible barriers between us and the classical past or the Oriental present. Compared with this revolution the Renaissance is a mere ripple on the surface of literature. — C. S. Lewis, The Allegory of Love: A Study in Medieval Tradition, pp. 3-4 (paragraph break added for clarity).
In the course of his book, Lewis traces the doctrine of courtly love as it was presented in the Middle Ages. Courtly love, Lewis points out, was always adulterous (Lancelot’s love of Guinevere) or illicit in some way (e.g., Troilus’s pursuit of Criseyde). The medieval poets didn’t celebrate married love. After all, in a marriage there’s no more honouring of the wife (or so one would believe from what writers of the time say): the wife is now subject to the husband and there’s no longer any “romantic adoration” of the wife.
Lewis argues that the change in love poetry happened at the end of the medieval period and is fully effected only in the poetry of Edmund Spenser, whose Fairie Queene celebrates chastity and presents married love as the highest and truest love.
I don’t know if Lewis’s history is entirely accurate and I’ll leave it to the historians of medieval thought to debate. I do note that if Spenser and the late medievals began to praise romantic love between husband and wife, they weren’t creating something new (as Lewis sometimes suggests); rather, they were returning to something as old as the Song of Songs.
Still, the history of love (and of allegorical love poetry) which Lewis traces is very interesting, not least because it shows us (as Lewis insists in the quotation above) that the way we think today isn’t simply “natural,” but flows from a lot of other factors in the past, factors which have shaped us without our knowing it.