FRONTONE. — The upper terminal part of the façade, generally triangular in shape so as to follow the slope of the roof.
It was adopted in the first Christian buildings (Constantinian basilicas, Syrian churches); but in Romanesque and Gothic churches, although the façade almost always terminates in a gable, the fronton is rarely present because there is no cornice separating it from the part below. The classical arrangement returns in the Renaissance. The curvilinear form (S. Maria dei Miracoli, S. Zaccaria) remains confined to Venice and the Venetian-influenced area in the second half of the 15th century. In the 17th century, the fronton also assumes that sense of movement and tension which characterizes the entire architecture of the period; broken forms appear (S. Maria in Campitelli in Rome) and mixtilinear ones, in which Borromini especially strove.
The Neoclassical age restores this element to the original simplicity of lines, but with a sense of coldness and rigidity.
In a broader sense, the term "frontone" is also given to the crowning element of windows, doorways, and altars. In windows, it appears sporadically even in the Paleochristian period (S. Salvatore in Spoleto) and Romanesque period (Florence Baptistery). The first example of a curvilinear fronton in windows is that of S. Salvatore al Monte by Cronaca; the motif is adopted by Michelangelo (S. Lorenzo sacristy) and rapidly diffused, even alternated with the triangular form on the same façade. The bizarre invention of the reversed frames is by Buontalenti (Door of the Supplications in the Palazzo degli Uffizi in Florence, 1580), and is entirely episodic; but already in this period begins the frequent use, in the 17th century, of the interrupted fronton to make room in the center for decorations or coats of arms.