Part 1

"In you is all gentleness, all perfection, so my spirit languishes perpetually by your absence. You are devoid of the gall of any faithlessness, you are sweeter than milk and honey, you are peerless among thousands, I love you more than any... So I truly want to tell you, if I could buy your life for the price of mine, I'd do it instantly, for you are the only woman I have chosen according to my heart."

This letter, written by a Bavarian nun to another nun, is certainly big on romantic love. There's another Bavarian nun letter that's even more than this, but it is NSFW! I'm not sure where the common myth that pre-modern societies lacked romance comes from - there was certainly romantic love in the Middle Ages, even if a lot of marriages were for power (for the wealthy) or stability (for the less wealthy) more than love. Romance novels from the 1700s is a strange place to put the beginning of romance, because it's one that ties an emotion - romantic attraction - to the emergence of a form of literature - the novel - and that doesn't work because romance is not confined to a particular literary format. Poems, letters, short stories, and epics are all equally valid media. I'm not particularly convinced - based on the available evidence - that there is much in a well-off 18th century European's experience of love that wasn't a feature of a well-off 12th century European's experience of love. That is not to say that our experience of romance is universal, just that medieval people do seem to have felt it in a similar way to us.

In Guigemar by Marie de France (a prominent 12th century author), one scene involves the hero finding it difficult to cope with the struggle of taking it slow, and being comforted by one of the lady's servants:

He lay awake all night, suffering and sighing; constantly he recalled in his heart her words and looks, her clear eyes and beautiful mouth, so that pain struck to his heart. … ‘My lord,’ she said, ‘you are in love: be careful you don’t hide it too much! You can love in such a way that your love will be well-lodged. Whoever wishes to love my lady must think most highly of her. This love will be admirable, if you are both loyal. You are handsome and she is beautiful.’

Knights were expected to be caring partners (though many were absolutely not), and this is reflected in books of advice for young men. When Edward III wrote a poem of advice to his son the Black Prince, he said:

For we hardly ever see a valiant man who does not or has not loved.

For many, this importance placed on love was not idle advice, but a true reflection of their feelings. For example, the 14th century knight Geoffrey de la Tour wrote of his long deceased partner, who probably died in the Black Death:

In the year of the Incarnation of our Lord 1371, I was in a garden, all heavy and full of thought, in the shadow, about the end of April, but I rejoiced a little in the melody and sound of the wild birds. They sang there in their language, as the thrustle, the thrush, the titmouse and other birds, which were full of mirth and joy. And their sweet songs made my heart lighten, and made me think of the time that is passed of my youth, how Love in great distress had held me, and how I was in her service many times full of sorrow and gladness, as many lovers are. But my sorrow was healed and my service well rewarded, for she gave me a fair wife that was both fair and good, which had knowledge of all honour and all good and all fair maintaining, and of all good was she bell and flower. And I delighted myself so much in her that I made for her songs, ballads, rondels, virelays, and diverse new things in the best ways that I could.

But Death, which makes war on all things, took her from me, that which has made me have many a sorrowful thought and great heaviness. And so it is more than twenty years that I have been full of great sorrow for her. For a true lover's heart never forgets the woman that he has once truly loved.

I think these alone demonstrate that people in pre-modern societies felt romantic attraction and love, and were happy to discuss that as an expected part of life. Whether it's Edward III's relationship advice for his son, the hopeless romantics of medieval fiction, or a knight being struck by memories of his dead wife as he walked through a garden, love was demonstrably an important part of their lives and they had a concept of romantic love.

Most surviving literature necessarily comes from the literate, which skews decidedly toward the elite. It was common for literate medieval people to write love letters or poems to their partners, especially if their profession or lifestyle involved either a lot of travel or being secluded in a fixed location. Because such people endured periods of their relationship being a long distance one, they tried to make up for it and keep the spark alive in the only manner that was available to them: writing to each other. Most of these letters and poems are romantic in a recognisably modern sense, and serious effort was put into producing them (after all, letters were expensive and logistically difficult to send, so they had to really count). For example, one 12th century poem concludes:

You are mine, I am yours, of this you shall be sure. You are locked within my heart, the little key is lost, and there within you must forever rest.

Although many of our examples of medieval love letters and poems are in the form of loose letters that happen to survive tucked between the pages of manuscripts or in private collections, it is worth noting that love letters were considered a form of literary art worthy of copying, preserving, and studying. That poem is preserved because someone thought it was good enough to be worth studying as a good example of romantic literature and had it copied into a manuscript. The monk Guibert of Nogent, an early 12th century intellectual based in the area around Laon in France, recalls that during his lifetime there was a serious craze for the art of romantic letter writing. Guibert was known for the complexity of his Latin, which meant that he was sometimes approached in the street by people asking for feedback on their love letters. Demand for the skill of writing love letters was so great that we have examples of templates for people to use, such as this one from the 9th century:

To my sweetest and dearest in everything, my honey-sweet [insert name here], I, in God’s name [insert name here], with dearest love and unceasing desire for you who are so very desirable to me. I send you through this letter greetings for as much joy as is contained within the fullness of our hearts, greetings which walk amidst the clouds and which the Sun and his Moon bring to you. When I go to bed, you are ever on my mind; and when I sleep, I dream always of you. Stay well in the day and sleep well at night. Always keep your boyfriend in mind, and do not forget him, for I do not forget you. Come up with a clever way, and I’ll one more acquire, through what kind of trickery we’ll fulfil our desire!

Not exactly subtle, but pretty standard for this sort of letter. Because these letters are a symptom of long distance relationships rather than people who could see each other whenever they liked, a very common theme is the idea of finding a way to meet. There are hundreds of surviving love letters from the Middle Ages, and the literature of love was evidently an important part of literary culture. I'm sure there are various theoretical frameworks that could define romance so narrowly as to exclude the experience of love in certain societies and cultures. However, looking at their own documents, people in the Middle Ages certainly loved others, had a concept of romance, and romantic love was a desirable aspect of their lives. While the manner in which a European person from 1200, 1700, and 2021 experience romantic love (and particularly the process of finding it or language used to express it) might be a bit different, the concept itself is not so different.

To answer this question, I think it would be worth familiarising ourselves with the History of Emotions. I am quite certain your professor had this in mind - it is a large and growing sub-discipline and most historians are well aware of it.

In the words of one research centre in Berlin, this research "rests on the assumption that emotions – feelings and their expressions – are shaped by culture and learnt/acquired in social contexts. What somebody can and may feel (and show) in a given situation, towards certain people or things, depends on social norms and rules. It is thus historically variable and open to change." In other words, how we talk and think about emotions, including "love", and even how we feel them, is in large part shaped by the cultural and social context, and therefore by the historical period, in which we live.

Theoretically, there is a degree of disagreement about how that shaping process actually works. Some treat emotions as wholly shaped by the socio-cultural environment (or, alternatively, view emotional expressions shaped by the environment as the only thing that we as historians can access). Others combine the cultural regulation of emotions with their inherent embodiedness. Usually this latter group don't see emotions themselves as universal biological constants but rather see biology as determining to some degree how the socio-cultural shaping process takes place within the individual. As such the field borrows heavily from other disciplines. Not just anthropology and sociology but also psychology and neuroscience. A good, if at times quite complex, introduction, is Jan Plamper's The History of Emotions: An Introduction.

The field rests on a rejection of how many earlier historians thought about emotions in the past: a rejection of "universalism", which saw emotions as something experienced uniformly by all persons, as universal constants in human biology; and a rejection of the metanarrative of the "civilizing process" in which emotions are gradually mastered by reason in a linear progression towards modernity.

While the other responses are correct to point out all kinds of sources that seem to express "romantic love", historians of emotions would resist the temptation to imagine or project our own conceptions and feelings of what that entails onto the past. Instead, they would interrogate the norms of expression around "love" (or however historical subjects describe the emotion - something that itself varies over time and by culture/language, without there always being a direct translation), and ask how they differed from prior or later periods or from other cultures.

In this case, I know of only a few interesting examples of scholarship on romantic love. One is William Reddy's The Making of Romantic Love: Longing and Sexuality in Europe, South Asia, and Japan, 900-1200CE, which traces the birth of "romantic love" as a "movement of covert resistance" against the Catholic Church's reforms around marriage and sexual desire. This might be an interesting reference for those intrigued by the other post's examples from this period!

For your professor's comment, there is indeed a convincing body of literature that traces our current modern conceptions of various emotions to the 1700s and later. William Reddy's earlier book The Navigation of Feeling, a deeply theoretical work and an early example of extensive engagement with recent neuroscience, included plenty on Romanticism and could be read in this way. You might also look at the collection of essays edited by Susan Matt, A Cultural History of Emotions in the Age of Romanticism, Revolution, and Empire, which looks at the period of 1780-1920 as the period when the modern conceptions of emotions that we still use/feel first took shape. I am sorry that I don't have more references - my current project is not on emotions and it has been some time since I was a historian of emotions. But if you search for general introductions to this field, the period you're interested in will feature heavily.

So, was "romantic love" not a "concept until the invention of the (romance) novel in the 1700s"? The answer surely requires us to define "romantic love". More importantly, though, we need to assess how our historical subjects expressed and conceived of it. Did they think of it differently? I am fairly sure most historians of emotions will agree that there are changes in the expression of romantic love in the 1700s onwards which help us to understand our current conceptions. Whether that means there was no "romantic love" before that depends on how we define it and whether we can include earlier conceptions within our definitional parameters, and I think is likely a question of semantics.