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
Doric order Doric order had not been very widely used, though "Tuscan" types of round capitals were always popular, especially in less formal buildings. It was sometimes used in military contexts, for example the Royal Hospital Chelsea (1682 onwards, by Christopher Wren). The first engraved illustrations of the Greek Doric order dated to the mid-18th century. Its appearance in the new phase of Classicism brought with it new connotations of high-minded primitive simplicity, seriousness of purpose, noble sobriety. In Germany it suggested a contrast with the French, and in the United States republican virtues. In a customs house, Greek Doric suggested incorruptibility;