In the latin and italian versions of De pictura, written between 1435 and 1436, Leon Battista Alberti puts down in writing the basic geometric elements for making a linear perspective construction in painting: the vanishing point, the picture plane, a method for gauging the distances. Of particular interest in the Alberti’s procedure is the condition that both the viewers and the painted figures appear to be in the same ground plane. North of the Alps in the fourth decade of fifteenth century Jan Van Eyck also applies the same principle in his innovative paintings as The Arnolfini Portrait.