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
Tuscan order its overall proportions, intercolumniation and simpler entablature, it follows the ratios of the Ionic. This strong order was considered most appropriate in military architecture and in docks and warehouses when they were dignified by architectural treatment. Serlio found it "suitable to fortified places, such as city gates, fortresses, castles, treasuries, or where artillery and ammunition are kept, prisons, seaports and other similar structures used in war." Not all modern writers accept the Tuscan order, and it is sometimes called "Doric" even by those aware of the distinction. From the perspective of these writers, the Tuscan order was an older primitive