The Notebooks of Leonardo Da Vinci — Complete
his_ Trattato _and besides the taste for domes prevailing at that
time, it seems likely that the intended erection of some building of
the first importance like the Duomos of Pavia and Como, the church
of Sta. Maria delle Grazie at Milan, and the construction of a Dome
or central Tower_ (Tiburio) _on the cathedral of Milan, may have
stimulated Leonardo to undertake a general and thorough
investigation of the subject; whilst Leonardo's intercourse with
Bramante for ten years or more, can hardly have remained without
influence in this matter. In fact now that some of this great
Architect's studies for S. Peter's at Rome have at last become
known, he must be considered henceforth as the greatest master of
Dome-Architecture that ever existed. His influence, direct or
indirect even on a genius like Leonardo seems the more likely, since
Leonardo's sketches reveal a style most similar to that of Bramante,
whose name indeed, occurs twice in Leonardo's manuscript notes. It
must not be forgotten that Leonardo was a Florentine; the
characteristic form of the two principal domes of Florence, Sta.
Maria del Fiore and the Battisterio, constantly appear as leading
features in his sketches.
The church of San Lorenzo at Milan, was at that time still intact.
The dome is to this day one of the most wonderful cupolas ever
constructed, and with its two smaller domes might well attract the
attention and study of a never resting genius such as Leonardo. A
whole class of these sketches betray in fact the direct influence of
the church of S. Lorenzo, and this also seems to have suggested the
plan of Bramante's dome of St. Peter's at Rome.
In the following pages the various sketches for the construction of
domes have been classified and discussed from a general point of
view. On two sheets: Pl. LXXXIV (C.A. 354b; 118a) and Pl. LXXXV,
Nos. 1-11 (Ash. II, 6b) we see various dissimilar types, grouped
together; thus these two sheets may be regarded as a sort of
nomenclature of the different types, on which we shall now have to
treat._
_1. Churches formed on the plan of a Greek cross.
Group I.
Domes rising from a circular base.
The simplest type of central building is a circular edifice.
Pl. LXXXIV, No. 9. Plan of a circular building surrounded by a
colonnade.
Pl. LXXXIV, No. 8. Elevation of the former, with a conical roof.
Pl. XC. No. 5. A dodecagon, as most nearly approaching the circle.
Pl. LXXXVI, No. 1, 2, 3. Four round chapels are added at the
extremities of the two principal axes;--compare this plan with fig.
1 on p. 44 and fig. 3 on p. 47 (W. P. 5b) where the outer wall is
octagonal.
Group II.
Domes rising from a square base.
The plan is a square surrounded by a colonnade, and the dome seems
to be octagonal.
Pl. LXXXIV. The square plan below the circular building No. 8, and
its elevation to the left, above the plan: here the ground-plan is
square, the upper storey octagonal. A further development of this
type is shown in two sketches C. A. 3a (not reproduced here), and in
Pl. LXXXVI, No. 5 (which possibly belongs to No. 7 on Pl. LXXXIV).
Pl, LXXXV, No. 4, and p. 45, Fig. 3, a Greek cross, repeated p. 45,
Fig. 3, is another development of the square central plan.
The remainder of these studies show two different systems; in the
first the dome rises from a square plan,--in the second from an
octagonal base._
_Group III.
Domes rising from a square base and four pillars. [Footnote 1: The
ancient chapel San Satiro, via del Falcone, Milan, is a specimen of
this type.]_
a) First type. _A Dome resting on four pillars in the centre of a
square edifice, with an apse in the middle, of each of the four
sides. We have eleven variations of this type.
aa) Pl. LXXXVIII, No. 3.
bb) Pl. LXXX, No. 5.
cc) Pl. LXXXV, Nos. 2, 3, 5.
dd) Pl. LXXXIV, No. 1 and 4 beneath.
ee) Pl. LXXXV, Nos. 1, 7, 10, 11._
b) Second type. _This consists in adding aisles to the whole plan of
the first type; columns are placed between the apses and the aisles;
the plan thus obtained is very nearly identical with that of S.
Lorenzo at Milan.
Fig. 1 on p. 56. (MS. B, 75a) shows the result of this treatment
adapted to a peculiar purpose about which we shall have to say a few
words later on.
Pl. XCV, No. 1, shows the same plan but with the addition of a short
nave. This plan seems to have been suggested by the general
arrangement of S. Sepolcro at Milan.
MS. B. 57b (see the sketch reproduced on p.51). By adding towers in
the four outer angles to the last named plan, we obtain a plan which
bears the general features of Bramante's plans for S. Peter's at
Rome. [Footnote 2: See_ Les projets primitifs _etc., Pl. 9-12.] (See
p. 51 Fig. 1.)
Group IV.
Domes rising from an octagonal base.
This system, developed according to two different schemes, has given
rise to two classes with many varieties.
In a) On each side of the octagon chapels of equal form are added.
In b) The chapels are dissimilar; those which terminate the
principal axes being different in form from those which are added on
the diagonal sides of the octagon.
a. First Class.
The Chapel_ "degli Angeli," _at Florence, built only to a height of
about 20 feet by Brunellesco, may be considered as the prototype of
this group; and, indeed it probably suggested it. The fact that we
see in MS. B. 11b (Pl. XCIV, No. 3) by the side of Brunellesco's
plan for the Basilica of Sto. Spirito at Florence, a plan almost
identical with that of the_ Capella degli Angeli, _confirms this
supposition. Only two small differences, or we may say improvements,
have been introduced by Leonardo. Firstly the back of the chapels
contains a third niche, and each angle of the Octagon a folded
pilaster like those in Bramante's_ Sagrestia di S. M. presso San
Satiro _at Milan, instead of an interval between the two pilasters
as seen in the Battistero at Florence and in the Sacristy of Sto.
Spirito in the same town and also in the above named chapel by
Brunellesco.
The first set of sketches which come under consideration have at
first sight the appearance of mere geometrical studies. They seem to
have been suggested by the plan given on page 44 Fig. 2 (MS. B, 55a)
in the centre of which is written_ "Santa Maria in perticha da
Pavia", _at the place marked A on the reproduction.
a) (MS. B, 34b, page 44 Fig. 3). In the middle of each side a column
is added, and in the axes of the intercolumnar spaces a second row
of columns forms an aisle round the octagon. These are placed at the
intersection of a system of semicircles, of which the sixteen
columns on the sides of the octagon are the centres.
b) The preceding diagram is completed and becomes more monumental in
style in the sketch next to it (MS. B, 35a, see p. 45 Fig. 1). An
outer aisle is added by circles, having for radius the distance
between the columns in the middle sides of the octagon.
c) (MS. B. 96b, see p. 45 Fig. 2). Octagon with an aisle round it;
the angles of both are formed by columns. The outer sides are formed
by 8 niches forming chapels. The exterior is likewise octagonal,
with the angles corresponding to the centre of each of the interior
chapels.
Pl. XCII, No. 2 (MS. B. 96b). Detail and modification of the
preceding plan--half columns against piers--an arrangement by which
the chapels of the aisle have the same width of opening as the inner
arches between the half columns. Underneath this sketch the
following note occurs:_ questo vole - avere 12 facce - co 12
tabernaculi - come - _a_ - _b_. _(This will have twelve sides with
twelve tabernacles as_ a b._) In the remaining sketches of this
class the octagon is not formed by columns at the angles.
The simplest type shows a niche in the middle of each side and is
repeated on several sheets, viz: MS. B 3; MS. C.A. 354b (see Pl.
LXXXIV, No. 11) and MS. Ash II 6b; (see Pl. LXXXV, No. 9 and the
elevations No. 8; Pl. XCII, No. 3; MS. B. 4b [not reproduced here]
and Pl. LXXXIV, No. 2)._
_Pl. XCII, 3 (MS. B, 56b) corresponds to a plan like the one in MS.
B 35a, in which the niches would be visible outside or, as in the
following sketch, with the addition of a niche in the middle of each
chapel.
Pl. XC, No. 6. The niches themselves are surrounded by smaller
niches (see also No. 1 on the same plate).
Octagon expanded on each side.
A. by a square chapel:
MS. B. 34b (not reproduced here).
B. by a square with 3 niches:
MS. B. 11b (see Pl. XCIV, No. 3).
C. by octagonal chapels:
a) MS. B, 21a; Pl. LXXXVIII, No. 4.
b) No. 2 on the same plate. Underneath there is the remark:_
"quest'e come le 8 cappele ano a essere facte" _(this is how the
eight chapels are to be executed).
c) Pl. LXXXVIII, No. 5. Elevation to the plans on the same sheet, it
is accompanied by the note:_ "ciasscuno de' 9 tiburi no'uole -
passare l'alteza - di - 2 - quadri" _(neither of the 9 domes must
exceed the height of two squares).
d) Pl. LXXXVIII, No. 1. Inside of the same octagon. MS. B, 30a, and
34b; these are three repetitions of parts of the same plan with very
slight variations.
D. by a circular chapel:
MS. B, 18a (see Fig. 1 on page 47) gives the plan of this
arrangement in which the exterior is square on the ground floor with
only four of the chapels projecting, as is explained in the next
sketch.
Pl. LXXXIX, MS. B, 17b. Elevation to the preceding plan sketched on
the opposite side of the sheet, and also marked A. It is accompanied
by the following remark, indicating the theoretical character of
these studies:_ questo - edifitio - anchora - starebbe - bene
affarlo dalla linja - _a_ - _b_ - _c_ - _d_ - insu. _("This edifice
would also produce a good effect if only the part above the lines_ a
b, c d, _were executed").
Pl. LXXXIV, No. 11. The exterior has the form of an octagon, but the
chapels project partly beyond it. On the left side of the sketch
they appear larger than on the right side.
Pl. XC, No. 1, (MS. B, 25b); Repetition of Pl. LXXXIV, No. 11.
Pl. XC, No. 2. Elevation to the plan No. 1, and also to No. 6 of the
same sheet._
_E. By chapels formed by four niches:
Pl. LXXXIV, No. 7 (the circular plan on the left below) shows this
arrangement in which the central dome has become circular inside and
might therefore be classed after this group. [Footnote 1: This plan
and some others of this class remind us of the plan of the Mausoleum
of Augustus as it is represented for instance by Durand. See_ Cab.
des Estampes, Bibliotheque Nationale, Paris, Topographie de Rome, V,
6, 82._]
The sketch on the right hand side gives most likely the elevation
for the last named plan.
F. By chapels of still richer combinations, which necessitate an
octagon of larger dimensions:
Pl. XCI, No. 2 (MS. Ash. 11. 8b) [Footnote 2: The note accompanying
this plan is given under No. 754.]; on this plan the chapels
themselves appear to be central buildings formed like the first type
of the third group. Pl. LXXXVIII, No. 3.
Pl. XCI, No. 2 above; the exterior of the preceding figure,
particularly interesting on account of the alternation of apses and
niches, the latter containing statues of a gigantic size, in
proportion to the dimension of the niches.
b. Second Class.
Composite plans of this class are generally obtained by combining
two types of the first class--the one worked out on the principal
axes, the other on the diagonal ones.
MS. B. 22 shows an elementary combination, without any additions on
the diagonal axes, but with the dimensions of the squares on the two
principal axes exceeding those of the sides of the octagon.
In the drawing W. P. 5b (see page 44 Fig. 1) the exterior only of
the edifice is octagonal, the interior being formed by a circular
colonnade; round chapels are placed against the four sides of the