Balusters, in general, are defined as the distinctive supports of balustrades (Pl. 1a). Renaissance balusters, unlike the extravagant varieties developed during the Baroque period, are simple in form, usually consisting of a double bulb, although single bulb variants known as ‘dropped’ balusters because of their low centre of gravity are not uncommon (Pl. 1b).
Balustrades can be found as parapets — fronting balconies or flanking staircases — and also as the decorative crowning features of façades. While they are physically sturdy, they are not blind architectural barriers, so that they are well suited in cases where through-vision is necessary but direct access undesirable. The balustrade, however, was only one of several possibilities for Renaissance architects. The traditional medieval railing, with colonnettes rather than balusters, was still in common use up to the end of the fifteenth century, while metal-work grilles and the open lattice or solid parapet wall provided further alternatives (Pl. 3j).