Leaving aside the special category of art that sought to depict a biblical scene or Christian image, most art before the end of the nineteenth century was understood in terms of a response: a response to people in the form of portraits or a response to nature depicted in landscapes or still life. Expressionism is a term used to describe the move away from art as a response, to art as the expression of powerful personal emotion through the use of colour and line. Although its antecedents lie in the late nineteenth century, especially in the work of Van Gogh, as a movement it is particularly associated with a number of artists working in the period shortly before and after World War I, beginning with the Die Brücke (The Bridge) movement in 1905. In the work of these artists, as well as some startling use of colour there was a more pronounced element of distortion in the human figure, often with overtones of violence. The importance of this art from a religious point of view was highlighted by the theologian Paul Tillich. He argued that there are two forms of art that cannot serve specifically Christian purposes. One is naturalism, as for example we have in the landscapes and portraits of the eighteenth century. Naturalism is concerned with depicting the world as it appears to our physical eyes and, as such, does not seek to lift up our eyes to what might lie behind, beyond and within the physical.