It will be seen that in the judgment of the greatest painters, decoration in a portrait should be altogether subordinated to the truthful representation of character, this practice being only varied when the personage portrayed is of public importance, and the portrait is required more or less as a monument. The rule is natural and reasonable, being based upon the universal agreement that the all-important part of a man comprehended by the vision is his countenance. But the rule only strictly applies to a single figure portrait, for when the painter goes beyond this, and executes a double portrait or a multiple group, he restricts the scope of his art. Other things being equal a double portrait is necessarily inferior art to a single figure picture, since the dual objective complicates the impression of the work on the brain, and the only remedy, or partial remedy, for this drawback possessed by the painter is to introduce accessories and arrange his group in a subject design. This plan results in detracting from the force of the actual portraits, as it divides the attention of the observer, but there is no help for it unless one is content with the representation of the figures in a stiff and formal way which extinguishes the pictorial effect of the work. The greatest artists have avoided dual or triple portrait works where possible except in cases of gatherings of members of the same family, as one of these groups may be regarded as a unity by the observer. Nevertheless in his picture of Leo X., and the two younger Medici,[a] Raphael was careful to subordinate the cardinals so that they should appear little more than accessories in a painting of the Pope; an example which was followed not quite so successfully by Titian in his triple portrait of Paul III. with the two brothers Farnese.[b] A group of two persons who are in some way associated with each other, though unconnected in action, rarely looks out of place, as in the pictures of father and son, or of two brothers, painted by Van Dyck, or in The Ambassadors of Holbein,[c] but no painter has yet succeeded in producing a first-class work of art out of a multiple portrait group when the personages represented are unconnected with each other, either directly in action, or indirectly through association derived from the title. The picture of Rubens representing Lipsius and three others, would appear much more stiff and formal than it is, without one of the two titles given to it, notwithstanding the general excellence of the composition.[d] When the figures introduced are very numerous, as in the many groups of civic organizations painted by Hals, Ravesteyn, and others, the compulsory formality seriously detracts from the æsthetic value of the works, however superior they may be in execution, or whatever the connection of the personages represented; and when we come to such crowded paintings as Terburg's Signing the Peace of Münster,[e]