Northern exposure

As with many celebrated artists, the reputation of Caspar David Friedrich has waxed and waned, both during his lifetime and since but, most recently, it has been steadily in the ascendent. This follows the publication, in 1973, of Robert Rosenblum's ground-breaking book, Modern Painting and the Northern Romantic Tradition. Rosenblum set out to do nothing less than shift modern art's centre of gravity northwards from Paris, from the southern hedonism of Picasso and Matisse, to northern melancholy; and Friedrich, with his austere Lutheran sensibility, was a king-pin in his argument.

Though he is widely regarded as the foremost 19th-century German Romantic artist, Friedrich was born "a subject of the King of Sweden" in Greifswald on the Baltic coast, in 1774. He studied in Copenhagen, though from 1798 he was based in Dresden, where he remained for the rest of his life. When he travelled he went back north to the Baltic, or walked in the mountains, but never ventured as far south as Italy, despite the prompting of Goethe and others. If he did, he feared, returning home would "be like burying oneself alive".

From the first he imbued his powerfully atmospheric, moody landscape and nature imagery with religious feeling. But while he was never other than a devout believer, his radical translation of spiritual experience from traditional religious iconography to the vastness of nature itself unsettled and dismayed those who expected a more overt religiosity. His "iconisation" of landscape, lifting it from its various genre associations, has since been recognised as a major part of his artistic achievement.

His remarkable pictures invite us to identify with the tiny figures he depicts, backs turned toward us, absorbed in contemplation of the overwhelming mysteries of nature. Often this is effected in compositions of such startling formalism and simplicity that Rosenblum could plausibly imply a direct connection between Friedrich's paintings and Mark Rothko's sonorous abstract voids. Heinrich von Kleist famously wrote of his The Monk by the Sea that "since it has, in its uniformity and boundlessness, no foreground but the frame, it is as if one's eyelids had been cut off."

Friedrich married Caroline Bommer in 1818, when his artistic abilities were at their height. The couple had three children by the time, just six years later, Friedrich became seriously ill. A stroke more seriously debilitated him in 1835, by which time, his best work long behind him, he had become gloomy, abrasive and - by all accounts unjustifiably - obsessively suspicious of Caroline, dying an embittered man in 1840.

Hofmann painstakingly constructs a portrait of a more rounded, complex figure than that of a didactic Lutheran sermonising through imagery laden with allegory. He certainly tackles that aspect of the work, but also Friedrich's concern with German patriotism (clumsily if understandably appropriated by the Third Reich), and, in a fascinating section of his text, the view of women, individuality and companionship that emerges in his art.

While that art unmistakeably stemmed from the dogmatic certainty of his Lutheran-Evangelical faith and, as Hofmann puts it, the painter's choices had already been made, he remained more open with regard to the viewers of his paintings. His pictures "were not tracts", Hofmann suggests, referring several times to Friedrich's expressed opinion that "an artist's gift, perhaps his greatest, is to stimulate the spirit, and arouse thoughts, feelings and sensations in the viewer, even if they are not his own." Thus the artist's own words, he suggests, open a way to multiple interpretations. The work of art is an open means of self-questioning for the viewer.

Hofmann's book is the first major monograph on Friedrich in many years. It is superbly produced, and illustrated with large-scale reproductions of all his important works. Drawing on an impressive breadth of knowledge, it convincingly situates him in his time and brilliantly analyses the nature and significance of the formalised spatial architecture of his pictures, offering an invaluable account of an enduringly relevant artist who commented of his own discipline: "Art may be a game, but it is a serious game."

Aidan Dunne is Art Critic of The Irish Times