There were two broad classes of Tuscan water fountains known in the fifteenth century: the freestanding or "isolated" type, designed for the center of a piazza, court, or garden; and the "engaged" or wall fountain, placed against a wall at the end of a square or courtyard.
The only example of a Florentine wall fountain from this period is the handsome structure of pietra serena in the court of the Palazzo Orlandini, now the property of the Banca del Monte dei Paschi. This consists of a single niche crowned by an arch and framed by classical pilasters, the wall and floor tileswater falling from an ornamental spout within the recess into a basin placed at its foot.
Structures similar to wall fountains, known as lavabos, abound in Florentine churches and monasteries. These, although supplied with running water, are not true fountains; for the water, controlled by a tap, is turned on only when needed, not utilized for continuous display. The lavabo was a lavatory at which the celebrant washed his hands before consecrating the host. Consequently the basin was placed much higher than in the true wall fountain. The lavabo had its secular counterpart in the acquaio or lavatory of the private palace.
Few isolated fountains of the fifteenth century have been preserved intact. Museums and private collections contain scattered basins and figures in the style of the Florentine Quattrocento, pierced for the passage of water. With the help of contemporary Italian engravings, paintings, and drawings in which fountains are represented, we can reconstruct the most common forms. From the small size of both statues and basins, it is evident that they were intended for private courts or gardens.
The Florentine fountain figures that survive from that period are mainly variations on the popular theme of the putto. However, representations of fountains in contemporary Italian art indicate that a wide range of subjects, generally based upon classical prototypes, was known in the Quattrocento.
A jet of water was usually connected in some way with the statue. At times it fell from some accessory held by the figure, trickling from an urn or spouting from a fish or dolphin. Often it issued directly from the human figure in motifs scarcely acceptable to modern taste, but very popular in the Renaissance.
In wall fountains and lavabos, sculptors simply adapted the forms of contemporary altarpieces and wall tombs. With freestanding fountains, however, they had to face new challenges. Chief of these was the necessity for a 360-degree treatment of figures. In most of the sculpture produced in the Quattrocento this problem did not arise, since freestanding figures of that period were usually wall and floor tiles given an architectural background, or set within a niche, where a frontal treatment sufficed. A statue decorating the summit of an isolated fountain, in the center of a court or garden, was another matter. It was approached from various angles, and called for a more complex handling which would make it interesting from many points of view. This was a difficult technical problem, and was not solved at a single stroke. Rather, the skill apparently evolved over time, as evidenced in the surviving statuary from that period.