CAPITELIO. - It is the architectural element that serves to connect a support, whether it be a column or a pier, with the architrave or the springing lines of an arch. The form of capitals varies according to architectural styles and periods. In the architecture of the Greeks and Romans the capital assumed determined forms and proportions in relation to the other elements of the structures (v. ORDINI ARCHITETTONICI). The builders of Paleo-Christian edifices, whether basilican or baptisterial, used capitals entirely similar to those of contemporary pagan buildings. From the 4th century onward, Christian symbols were also incorporated into the decoration of capitals.
In the first half of the 5th century, a type of capital was particularly in vogue which Strzygowski termed "Theodosian" because it first appeared and was widely used during the reign of Theodosius II (408-50). This is a composite capital adorned with a double row of eight leaves of fat and spiny acanthus, whose tips, somewhat tapered from the base, curve strongly. The leaves of the lower row are placed in the intervals of those of the upper row, on four of which rest the volutes of the capital. Instead of a series of eggs, the capital is surrounded at the top by small generally pentolobate leaflets, some of which sometimes bear a small cross carved on them, as can be seen, for example, in some capitals of the church of St. Demetrio in Salonica. Created for the first time in the workshops of Constantinople, this type of capital soon spread to Greece and other regions of the East and also reached Italy: it is found indeed in the churches of Parenzo, Venice, and Ravenna. There are two examples also in Rome in the capitals reused in the tomb of Cardinal Venerio in S. Clemente.
In the Byzantine capital, which reached its greatest development in the 6th century during the Justinian age, the work of the chisel is almost completely replaced by that of the drill. The capitals, which assume the geometric form of a truncated pyramid or cone, have their faces covered with a fine network of interlacings, thus creating a chiaroscuro effect that makes the capital appear to have been worked "a giorno." Often the entire capital, more or less slender, resembles that of a wicker basket or an expanse of leaves and tendrils, which not infrequently rise, as can be seen in S. Vitale in Ravenna, from a central vase placed at the base of each face of the capital. Vine and acanthus leaves find in these capitals the most varied treatment, and it is not uncommon for them to be arranged so as to emphasize in the center of the face a circle, square, or rectangle containing a cross or, as is often found in the churches of Ravenna, some monogram.
In the Byzantine age the abacus above is carved from the same block, so that it forms a single piece with the capital: this new form has been given the name of "impost capital." The abacus is often covered with interlacings that spread over its faces like embroidery, or is adorned with various symbolic or decorative motifs.
Figurative or teratomorphic decoration appears in capitals of the Romanesque period.