Entablature being called petrification. The structure of the entablature varies with the three classical orders: Doric, Ionic, and Corinthian. In each, the proportions of the subdivisions (architrave, frieze, cornice) are defined by the proportions of the column in the order. In Roman and Renaissance interpretations, it is usually approximately a quarter of the height of the column. Variants of entablature that do not fit these models are usually derived from them. Pure classical Doric entablature is simple. The architrave, the lowest band, is split, from bottom to top, into the guttae, the regulae, and the taenia. The frieze is dominated by
Corinthian order colonettes within the same system. During the 16th century, a sequence of engravings of the orders in architectural treatises helped standardize their details within rigid limits. Sebastiano Serlio; the "Regola delli cinque ordini" of Giacomo Barozzi da Vignola (1507–1573); the "Quattro libri di Architettura" of Andrea Palladio, and Vincenzo Scamozzi's "Idea della Architettura Universale," were followed in the 17th century by French treatises with further refined engraved models, such as Perrault's. Corinthian order The Corinthian order is the last developed of the three principal classical orders of ancient Greek and Roman architecture. The other two are the Doric order which