To give credit where credit is due, some readers may spot echoes of the late Mike Ovey's CD1.1 lecture course in the pen portrait of romanticism below. They'd spot that with good reason. The section is included as a summary, and for the benefit of those not fortunate enough to have taken that course, before turning to the illustrative material which is my own contribution.
Romanticism is a wide-ranging movement from (mainly) the first half of the nineteenth century. It influenced literature, art, architecture, philosophy, theology, politics and more.