The conception of such ideas as are embodied in the _Adoration of the Lamb_, or in the _Triumph of the Church over the Synagogue_, at the Madrid Museum, would also have been quite beyond the pale of the more prosaic Jan's imagination. Jan, on the other hand, excelled in stating the reality of the visible world. Generalisations of human types or of landscape features are unknown to him. He was the first to fix upon his panels all the carefully studied and exquisitely wrought details of the actual world--sky and mountain and river, forest and fields, flowers and trees, and the churches and castles, houses and bridges, placed in Nature by human hands. It is scarcely too much to say that he was the first landscape-painter, just as he was the first portrait painter in the modern sense of the word--the first who could paint a scene so that it could be identified after the lapse of centuries, the first who could paint a portrait so that the model {30} stands before us living and breathing, in all his beauty or ugliness. To appreciate the keenness of his vision one has only to examine the marvellous Arnolfini group at the National Gallery, with its almost scientific treatment of softly diffused indoor light. A comparison of this picture, from the point of view of lighting, with anything that was painted before the days of the van Eycks will reveal perhaps the greatest step forward that is on record in the whole history of painting. {31} COLLABORATION OF THE BROTHERS When piecing together the lives of the brothers van Eyck, it is necessary to delve into a confusing mass of conflicting statements--evidence which is only in part to be relied upon, and the theories of those who have devoted a vast amount of time and labour to the unearthing, sorting, and arranging of such evidence as they have been able to lay their hands upon. Incomplete as the records are, we must, until further evidence has been discovered, accept the obvious conclusions from the indisputable data left to us. We have ten unquestionably genuine signed pictures by Jan, and a small group of others which may, from internal evidence, be safely ascribed to the same source. We know that the great _Adoration of the Lamb_, though designed in its entirety by Hubert, is the combined work of the two masters. We know also that the Copenhagen panel of Robert Poortier {32} was in Hubert's studio at the time of his death--perhaps unfinished. The remaining pictures generally accepted as genuine van Eycks have been variously ascribed to Hubert, or to Jan, or to their united efforts. In view of the fact that not a single really authenticated work by Hubert alone is known, special significance must be attached to a statement, several times repeated by early writers, that Hubert and Jan "continually painted on the same works."