While in the scale of the painter's art, portraiture ranks next to the higher branches of historical work, yet it is some distance behind them, for apart from the commonplace of scenic arrangement, the imagination of the portrait painter cannot be carried further than the consideration of added or eliminated details of form and expression in relation to a set subject. But these details are very difficult, and so it comes about that a good portrait involves a far greater proportion of mental labour than the result appears on the surface to warrant. It is indirectly consequent upon the complexity of his task that the work of the artist who devotes practically his whole time to portraiture, often varies so largely in quality. He paints some portraits which are generally appreciated, but as time goes on he is overwhelmed with orders which he cannot possibly fulfil without reducing the value of his work. He thus acquires a habit of throwing his whole power into his work only when the personage he represents is of public importance, or has a countenance particularly amenable to his manner or style. It is necessary that this fact should be borne in mind, otherwise erroneous standards are likely to be set up when artists like Van Dyck, Reynolds, or Romney, are referred to as examples. In a general sense nearly all painting where the human figure is introduced, is portraiture, and it has been so since soon after the middle of the fifteenth century, when artists commenced to use living men and women for secondary or accessory figures in sacred pictures. The increasing importance attached to the anatomy of the figure resulted in the extensive use of models, and so in a measure portraiture rose to be a leading feature in the work of the artist. The figures in the larger compositions of every kind by the greater painters of the late fifteenth and early sixteenth centuries, consist almost entirely of portraits of friends and acquaintances of the artists, the exceptions being the countenances of the Deity and Christ, which had to be modelled from accepted types, and those of the later Saints the character of whose features had been handed down by tradition. A few painters, as Raphael and Correggio, idealized the Virgin away from suggestion of portraiture, but others, as Del Sarto and Pontormo, even in this case took a wife or other relative as a model. The practice was continued by many artists in respect of central figures, till the end of the seventeenth century, after which time the identity of the figures was, as a rule, purposely lost. Nevertheless the figures, other than ideals, used in all good compositions, must necessarily be portraits or adaptations thereof, for only from life can superior representation of life be obtained.