The regulatory layout of the Porte Saint-Bernard - Paris, 1670 - by F. Blondel.

In Part 4 of his Lesson of Architecture, FranÁois Blondel sets out some of the fundamentals of the Art of the Ancients - which his most fervent supporters, such as CharlesEtienne Briseux, would illustrate forcefully - on the occasion of the restoration of monumental gates in Paris during the reign of Louis XIV: on the former route of Charles V's fortified walls, Louis XIV also had the Porte Saint-Bernard restored in 1670. F. Blondel's masterly presentation shows the extent to which the quest for harmony between the whole and its parts has reached an unequalled degree of perfection in terms of order, regularity and symmetry. All the more so as the architect had to retain the walls and pavilion of the old gateway, forcing him ‘to take different measurements from those that would otherwise have been taken. And to tell the truth, it took some thought to come up with something that would give the desired comfort, and whose ordinance was not to be despised’. It is this adaptability that is interesting and shows how this very classical approach is anything but rigid... The aim of this paper is to reveal the main geometric principles that the architect chose to create an harmonious building, according to the standards of the 'Ancients'...