Romanticism
An easily misunderstood word, 'Romanticism' is not a smart way of describing a Mills & Boon kind of art. Like so many other things in life, it helps to begin by describing what it was reacting to.
If we were alive in 1750 in Europe, we would have looked on the last 300 years as, well, changeable.
There had been an earthquake in the world of religion. In Western Europe, the Church was no longer the final authority. It has been argued that everyone had become their own Pope. The idea of the 'individual' was strengthened. Along with this Protestant Reformation (and its British counterpart) came a certain seriousness about life and suspicion of things sensual.
And in the world of art, there had been a rediscovery and reinterpretation of the classical world. This was symbolised in the classical marble sculpture: austere, restrained and ordered. With notable exceptions, the Renaissance world was one which cultivated a taste for artistic activity stripped bare of emotion.
Finally, there was the world of ideas, science and learning. The 18th century in Europe and North America is one of the few periods of Time which named itself - the Enlightenment. The superstitious world of the Middle Ages was rejected in favour of a world informed by objective knowledge, experiment and observation, and logic.
But however powerful any moment of change is, there will always come a reaction to it.
One such reaction was Romanticism. This informal movement sought to reclaim passion and feeling in the arts. It has been described as 'injecting art with emotion'. Where there had been restraint, the feelings of the writer or artist were now paramount. Poets such as Wordsworth, Keats and Shelley expressed intense emotions in their work and engendered similar feelings in their readers. If they sometimes seem excessive to us, in its time their style was seen as a refreshing break with what had gone before.
I realise that I have written that so casually - that they conveyed and inspired emotions through their work - but isn't it extraordinary? Isn't it another dose of magic that (in our case) artists could do such a thing with paint and canvas? If we take it for granted it's partly because its no longer a new idea, but also because we have become a little jaundiced by the way that advertising exploits this ability. Using small puppies to sell toilet paper applies the same principle.
No. Romanticism introduced something as show-stopping as single-point perspective.