In a fairly large number of seventeenth century Netherlandish portraits a motif can be seen which has hitherto been disregarded in art history. It is the ball on a straight-sided pillar at the end or in the middle of a balustrade. Most of such balls stand on a plinth; some are placed directly on the pillar. The sitters are portrayed in an evident relationship to such balustrade balls, sometimes with a hand on the ball, sometimes pointing demonstratively at it. In the author's opinion this architectural element - the stone ball and its straight-sided support cannot have had a merely decorative function as a rule, at least not when used in portraits. He contends that it was meant as a derivative or a substitute, with respect to both form and content, of a motif which occurs in various guises in emblems and occasionally in kindred literature, consisting of a ball and cube depicted in close proximity. In certain cases, for example in the writings ofPers, Vacnius, Rollenhagen, Oudaan, Boschius and Spinniker, their union is consummated, the ball sitting on the cube (or another straight-sided body) and symbolizing wisdom, virtue in the general sense, patience, steadfastness or more particularly divinely inspired peace of mind. The configuration of the balustrade-ball and straight-sided support bestows these virtues upon the subjects of the portraits, meaning that these persons refer to such ideals or purport to possess these noble qualities already. Their poses and gestures can be extremely eloquent. Even so, these persons and their remarkable attribute supply no more than approximate information. While the virtues in question are always precisely specified and dcscribed in literature, such is naturally not the case in portraiture. Basically, the specific meaning or nuance of meaning embodied in a particular portrait can never be established with certainty. Going by source material, however, we may assume that one of the aforesaid virtues and qualities is alluded to, very likely tranquillitas animi, peace of mind.