Religious subject matter is not central in 20th century art. One might therefore suspect that, for the avantgarde, the Spanish Civil War (1936-1939) would have eclipsed religion altogether. However, as Juan José Lahuerta argues in this book, the war caused a considerable revival of certain themes of religious art. In particular, it intensified Pablo Picasso's lifelong preoccupation with the subject of the Crucifixion.

The work of the Swiss surrealist painter Max von Moos (1903-1979) throws additional light on the paradox at hand. In 1938, i.e. one year after Picasso painted "Guernica," von Moos published an essay entitled "Religious Painting of Our Time" that addresses some of the critical issues then confronted by church art: issues of communication and expression, realism and abstraction that turn out to offer surprising insights into Picasso's art - if not into modern art altogether.