The balustrade, made up of reliefs in white marble from Seravezza with a mosaic background in majolica, reproduces the forms of a circular temple supported by pairs of small pillars: among these, the dance - a complex "farandola" - of seven groups of angels intertwines with uncontrollable energy, inspired by the putti-genietti of Roman tombs (certainly studied by the artist also during his Roman stay in 1432-33). The joy of the little angels is manifested in the freedom of their gestures with an insistent rhythm, depicted pictorially thanks to the "stiacciato", the complex perspective views, and the vibrating mosaic backgrounds. The inventive happiness of the design, of absolute creative freedom, is entirely attributable to Donatello, even though the execution was carried out by multiple hands in his workshop. The reliefs were removed from the exterior in 1970 due to worrying conditions, and placed in the Museum in 1976.