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
Simon Bosboom after the dismissal of Willem de Keyser, and in 1657, the year of Van Campen's death, Bosboom was promoted to city architect. Just as Hubertus Quellinus had done for the city hall in 1665, Bosboom published a small instructional booklet on architecture with engravings after Vincenzo Scamozzi entitled "Cort onderwys van de Vyf Colommen"; or "Short instruction on the five columns (Doric, Ionic, Corinthian, Tuscan, Composite)". His book earned him an honorary place in Cornelis de Bie's book of artists. He wrote that he helped Jacob van Campen and Artus Quellinus with decorations for the City Hall of Amsterdam, built