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Brunelleschi, The Man and His Work - The Cupolla Part I

When, in 1420, Filippo Brunelleschi was nominated superintendent of the construction of the cupola of the Florentine cathedral of Santa Maria del Fiore, the lines along which the construction was to be carried out had already been determined by what had been done previously (Arnolfo, Talenti). The diameter of the inner span (m. 41.50) is close to the maximum limit for any kind of masonry dome. From the times of the Pantheon there had been no examples of cupolas of such size.

Faith in these structures had been seriously undermined by the collapse, in 1346, of the dome of Hagia Sophia in Constantinople. In 1400 the Florentines had had to reinforce the structures of the Baptistery which had shown signs of giving way. Instead of recuperating precedent techniques, Brunelleschi invented a technique based on his knowledge of the "way of building" of the Romans as well as medieval (eastern) examples which he put at the service of a new concept and new kinds of technical, cultural, aesthetic problems, involved in the realization of the cupola.

Basically the construction of the dome depended on the use of a building technique capable of avoiding any dangerous discontinuity in the masonry (27,000 tons) and which would be able to circumvent the enormous problems involved in constructing a traditional wooden armature of the necessary dimensions.

Brunelleschi's structure of bricks laid in herringbone courses consisted of raising the wall in rings, each containing vertical elements for bonding the successive ring. The cupola was thus built as a self supporting growing form.

The dome is surprisingly modern: in this double shell, the lighter exterior cupola protects the inner cupola from the elements, while the two work together thanks to the powerful connecting ribs. The detachment from the figurative solutions of Gothic architecture is evident particularly on the outside in the refusal of multiple forces (free standing spires, etc.), in the rigor with which the convergence of the forces upwards is pursued, entrusting the formal solution to a formidable synthesis of continuous lines and accessory surfaces resulting in unity and free from any need to adapt to the more articulated and minute design of the structure underneath.

The first powerful expression of a conscious synthesis of two cultural worlds, Greek and Gothic, the cupola can in the end be defined as a sensitive diaphragm stretched between an external and an internal space, a diaphragm between one space and another. In their internal tension, the thrust and dynamic form (pointed arch and elliptical sector) engender a calculated equilibrium, a cupola that hovers and is suspended over the city, the result of the balance of all the forces.

The city is no longer a framework marked by the emergence of vertical points of reference (towers and campanili): the cupola, in its size and form, stands out and dominates everything else. The towers and the campanili (including Giotto's) all now relate to each other as a result of their relationship to the cupola which hovers between rooftops and sky at the center of the urban system and automatically become subordinate elements in a general plan.

The full meaning of this urban masterpiece, the cupola, is beautifully expressed in Leon Battista Alberti's splendid, synthetic definition in the context of the dedication of his treatise Della Pittura to Brunelleschi: "rising above the skies, ample to cover with its shadow all the Tuscan people". "Rising above" on the one hand expresses the meaning of the tension in the generating line chosen for the ribs, on the other the fact that the cupola is not dominated by the universal space but creates a space of its own which establishes all rapports and measures with respect to itself "Ample" expresses the fundamental qualification of distension and circularity of the hovering cupola, while on the other hand with "ample to" it immediately leads to the concept in which the size of this urban structure is seen in relation to the territory.

Moreover, the contrast established between the two terms ("rising above" - "ample to") expresses with marvelous conciseness the solution of all the forces, all the structures, all the equilibriums, of all the proportions both within itself and in relationship to the city, all the technical and structural problems, in the absolute abstraction and in the tension of the line of its cross section, etc. Lastly, Alberti's words stress the fact that the new formal dimensions also correspond to the new political dimension of the city.

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