Abstract
The part I of the present paper makes a perspective-analysis of the compositional structures of Brunelleschi's two major church architectures, San Lorenzo and Santo Spirito. The two works show, complementing each other, the whole system of the architect's design method, and in their structures' similarity and dissimilarity a slight transitional step to the modification of the method. Principal conclusions are as follows, [1] A set of perspective ratios (1 : 1 : 1…) and (1 : 1/2 : 1/3…) was integrally made clear of in both works' analyses. The ratios had been already but separately shown in our previous analyses of the Old Sacristy and the Portico dell' Ospedale degli Innocenti. [2] The "element-form", a compositional unity consisting of a pair of orders and a round arch which applies to the perspective ratios, is exactly the same in the compositions of the Old Sacristy, the Portico, and the San Lorenzo in its original projection. [3] In the composition of Santo Spirito, the sense of the "element-form", a priori determined and common to all compositional forms, received a modification, and here can be traced clearly a transitional step from the early to the later stage of this architect's design method.
