TRANSEPT AND CROSSING VAULTS
TRANSEPTS WITH TUNNEL VAULTS
Because of the close resemblance in plan and structure between them, the
transept was vaulted like the nave in by far the larger number of
instances. Thus in the Romanesque schools, where the nave was tunnel
vaulted, similar vaults were generally placed above the transept as
well. They were, moreover, well suited to this position, especially
where there were no transept aisles, for the outer walls running down to
the ground afforded them excellent support and also provided space for
windows of considerable size. It is not surprising, therefore, to find
the tunnel-vaulted transept the standard in Romanesque church
architecture, an example appearing even as far north as Jedburgh Abbey
in Scotland, although this was a church of the Norman school in which
the nave was probably originally roofed with wood.[282] Even in the
school of Perigord, where the naves are domed, the transept is
frequently covered with a tunnel vault as, for example, in the churches
of Souillac (Lot), Tremolac (Dordogne), and Vieux Mareuil (Dordogne), in
the cathedral of Angoulême, and perhaps originally in the cathedral of
Saint Front at Périgueux.[283] Occasionally, however, other forms
displace the tunnel vault in transept construction.
One of these appears in the abbey church of Cluny (Saône-et-Loire)
(early twelfth century). Here the bays of the transept, corresponding to
the side aisles of the church are tunnel vaulted, but beyond these,
there are two projecting bays, the inner one square and covered by an
octagonal dome on trumpet squinches, the outer covered with a tunnel
vault at a lower level[284] than that over the two bays adjoining the
crossing. Above the dome rises an octagonal tower and spire, and the
whole composition of this bay shows that it was intended to be a
flanking tower like those to be seen at Angoulême, Tréguier
(Côtes-du-Nord), and Exeter cathedrals. For such a tower, a dome is more
suitable than a tunnel vault, because it exerts less outward thrust.
This is also better distributed.
[Illustration: FIG. 49.--CLERMONT-FERRAND, NOTRE DAME-DU-PORT.]
A more original method of transept vaulting is to be seen in certain
churches of the school of Auvergne, among them Notre Dame-du-Port at
Clermont-Ferrand (Puy-de-Dôme) (eleventh and twelfth century) (Figs. 49,
50) and Saint Étienne at Nevers (Nièvre) (cir. 1097).[285] Here each arm
of the transept is divided into two distinct vaulting bays by a
transverse arch continuing the line of the outer wall of the church. All
the projecting portion is then covered by a tunnel vault, while that bay
which corresponds to a continuation of the side aisles is covered by a
half tunnel vault, its axis at right angles to the transept proper and
rising from above the crown of the intermediate transverse arch to the
springing of the crossing dome (Figs. 49-50). Such a vault has much to
commend it, for it is most logical in affording excellent abutment for
the dome, and at the same time it receives abutment from the tunnel
vault of the outer transept bay. Curiously enough, one church of the
school, namely that at Orcival (Puy-de-Dôme) (twelfth century),[286]
while following the main lines laid down by the vaults just described,
differs from them in having full tunnel vaults instead of half tunnels
abutting the dome. This is a less satisfactory form in that these vault
have to be excessively high in order to bring their thrusts to the
proper level, but they do possess the advantage of providing excellent
window space above the transept roofs.
[Illustration: FIG. 50.--CLERMONT-FERRAND, NOTRE DAME-DU-PORT.]
TRANSEPTS WITH RIBBED VAULTING
FIVE-PART RIBBED VAULTS
With the introduction of ribbed vaulting, examples of six-part vaults,
four-part vaults of rectangular and square plan and many forms of
complicated vaulting are to be found in the transept exactly as they
have been in the nave. Only those vaults which are unusual in character
will therefore be discussed. Of these the most important is the
five-part rectangular vault sometimes used as a termination of the
transept arm. From its appearance in Normandy, and its evident relation
to sexpartite vaulting, this method may be assumed to have arisen there.
The Abbaye-aux-Dames at Caen (early twelfth century) affords an example
of such a vault. It was evidently employed to subdivide the end walls
into bays similar to those in the remainder of the church, and thus
provide a uniform elevation and window arrangement throughout the
edifice. In spite of its uniformity the arrangement is an awkward one,
for it brings a pier directly in the center of the transept wall where
it would be more natural to find a door. The five-part vault did not,
therefore, become a general method of transept termination, though there
is a very fine example of its survival in the church of Saint Urbain at
Troyes (Aube) (cir. 1262-1300). It may even be that the desire for a
regular elevation of the bays led to the subdivision of the transept by
a row of central piers, such as those in the large church at Saint
Nicolas-du-Port (Meurthe-et-Moselle) (sixteenth century)[287] and in a
number of smaller examples, some of them of earlier date.[288]
SQUARE CHEVETS
Such a vault as that just described was, in a way, a sort of square
chevet.[289] It was built to provide a better arrangement of windows in
the terminal wall than would be possible beneath the transverse cell of
a regular four-or six-part vault. Nor was its use confined to the
transept for it is found with a varying number of cells at the end of
the nave and choir as well. Such Norman churches as Saint Georges at
Saint Martin-de-Boscherville (Fig. 51), Saint Étienne at Caen and Saint
Cross at Winchester (choir cir. 1135-1189) are examples of this,[290]
while the vaults of the transepts of Limburg Cathedral[291] (1235) and
that of the chapter house at Boscherville (Fig. 52) resemble a chevet
even more closely in that all but one of their severies are subdivided.
When the ribs all rise from the same level, the appearance of such a
vault is pleasing, but when,--as in the nave of Boscherville (Fig.
51),[292]--the intermediate ribs are shortened,
[Illustration: FIG. 51.--SAINT MARTIN-DE-BOSCHERVILLE, SAINT GEORGES.]
[Illustration: FIG. 52.--SAINT MARTIN-DE-BOSCHERVILLE, SAINT GEORGES,
CHAPTER-HOUSE.]
the effect is very unsatisfactory, though this shortening of the ribs
probably had a structural advantage in preventing the light from being
partly cut off, or the windows partly concealed by the radiants and the
masonry above them.
VAULTING OF SEMICIRCULAR TRANSEPTS
The vaulting of the transept naturally differs from that in the nave
when the former is given a semicircular termination. In Romanesque
transepts of this type, the vaults are in the form either of simple half
domes, or of tunnel vaults ending in such domes, according as the
transept arms are lengthened or left merely in the form of apses. Many
churches of both these types, but usually of small size, are to be found
in southern France,[293] while others appear in Italy and still others
in the north of Europe,[294] where such a church as that of Rolduc
(Belgium) was considered by its builders as built in a Lombard manner,
“scemate longo-bardico,”[295] indicating that the semicircular transept
was thought, at least, to be of Lombard origin. The most highly
developed transepts of this tunnel-vaulted, half-domed type are probably
those in the church of Saint Mary of the Capitol at Cologne, where a
groin-vaulted ambulatory is found around each transept apse. Somewhat
similar in plan are the transepts of Tournai cathedral in Belgium
(between cir. 1110-1170) (Fig. 53), except that here the surrounding
aisle is very narrow, and, more important still, the half dome is
replaced by a clumsy chevet vault with very heavy ribs, their haunches
raised to support a series of ramping and contracting tunnel vaults.
This construction is very similar to the framework of such a dome as
that of the Baptistery at Florence. Nor is it without advantages, since
it greatly reduces the vault thrusts and therefore renders unnecessary
the use of flying-buttresses,[296] and at the same time permits the
windows to rise above the level of its impost. The next semicircular
transept of importance is that of Noyon cathedral
[Illustration: FIG. 53.--TOURNAI, CATHEDRAL.]
(cir. 1140),[297] where there is a developed chevet of what will later
be called the buttressing ribbed type.[298] More developed still is the
south transept of Soissons cathedral (1176-1207), which possesses an
ambulatory in two stories with three bays of trapezoidal four-part
ribbed vaults corresponding to each principal vaulting bay. The transept
proper is covered by a rectangular vault[299] and a broken-ribbed chevet
with very broad window cells. Other examples of semicircular transepts
could be cited, both of the Romanesque and Gothic periods,[300] but
either they do not present any vaulting forms not already discussed or
they will be described in connection with the apse proper. That the plan
had a long lease of life, if not a very extensive usage, is shown by the
fact that it appears in such seventeenth century churches as that of the
Lycée Corneille at Rouen (beg. cir. 1614),[301] and is found in
numerous Renaissance churches in which the vaulting returns to the
earlier tunnel and half-dome forms.[302]
THE VAULTS OF TRANSEPT AISLES AND CHAPELS
As the transept developed in importance aisles were added, sometimes
merely along the east walls, but often along the west as well,[303] and
even across the ends, especially in churches where such tribunes
provided for a continuation of the triforium gallery.[304] In such
transepts the side aisles are vaulted just as those belonging to naves
of a corresponding period, and therefore require no discussion here.
More important are the chapels which open off of the transept, usually
from the eastern wall. In general these consist of a semicircular apse
either with or without one or more preceding bays. During the Romanesque
period such chapels were generally covered with a half dome sometimes
preceded by a tunnel vault as in Saint Georges-de-Boscherville, while
after the introduction of ribbed vaults, these and the chevet replace
the tunnel vaults and half domes in their respective positions.
Sometimes the chapels are square, especially in Cistercian churches.
They are then covered either with tunnel vaults, as in Kirkstall Abbey,
or with ribbed vaults in the Gothic period. Usually all these radiating
chapels are but one story in height, but in the cathedral of Laon, two
beautiful chapels more than a semicircle in plan and two stories in
height appear, one at the east end of both the north and south aisles of
the transept (Fig. 54). These chapels are vaulted with seven-part
chevets, and form, with the aisles and tribunes preceding them,
veritable churches inside of the cathedral. Chapels of similar
character, but practically a full circle in plan and vaulted with a
double chevet, are also to be seen in the two lower, stories of the
transept of Soissons cathedral. They open off of the aisles and
galleries through three slender arches, and the view into them from the
transept proper affords one of the finest examples of Gothic
perspective.
CROSSING VAULTS
[Illustration: FIG. 54.--LAON, CATHEDRAL, TRANSEPT TRIFORIUM CHAPEL.]
The intersection of the nave and transept was usually treated by the
Romanesque builders as a distinctive vaulting bay. Occasionally, in the
tunnel-vaulted churches, the builders allowed the vault of nave and
transept to intersect and form a groined vault at the crossing, as, for
example, in Saint Étienne at Beaugency (after 1050) (Loiret)[305] and in
the church of Boisney (Eure).[306] Groined vaults are also found in this
position in certain churches, like those of the Rhenish provinces, where
similar vaults are used in the nave. But as a general rule, the crossing
of the Romanesque church is covered by a dome resting on spherical
pendentives or squinches, either unraised or else placed on a drum,
which thus forms a lantern with windows to light the church interior.
There is no necessity for an extended discussion of raised and unraised
domes, since as far as construction is concerned they differ only in the
fact that when raised on a lantern they are somewhat more difficult to
support because the vaults of choir, nave, and transept no longer serve
as buttressing members. The custom, however, of erecting a tower even
above the raised domes offset to a large extent the thrusts which they
created.
Sometimes these Romanesque crossing domes are of circular plan and
supported on spherical pendentives. These are common in the school of
Perigord, where examples are afforded by the cathedral of Périgueux
(Fig. 1) or the abbey church of Solignac.[307] But the use of such domes
on spherical pendentives was not confined to Perigord. They are found in
Poitou and Les Charentes, in the Southwest, and even in Limousin.[308]
One of the best examples, and one in which there is a circular drum
below the dome, appears in the church of Le Dorat (cir. middle twelfth
century) (Haute-Vienne).[309] Very occasionally, also, the flat
triangular pendentive is used, as in Notre Dame at Chauvigny
(Vienne).[310]
LANTERN TOWERS
The use of a lantern tower with windows opening into the church below
its roof was destined to give rise to a number of interesting vaults.
That such towers existed in France as early as the sixth century, is
proved by the texts of Gregory of Tours and Fortunatus, in which such
lanterns are mentioned as existing over the churches of Saint Martin at
Tours, the cathedrals of Clermont-Ferrand, Narbonne, and Paris, as well
as at Bordeaux and Nantes,[311] while Rivoira’s contention[312] that the
church of San Salvatore or del Crocifisso at Spoleto dates from the
fourth century, if correct, would give an earlier though isolated
Italian example of such a feature. Whatever its origin, such a lantern
was a particularly pleasing feature of church construction, especially
in Romanesque churches, which were without direct light in the nave and
thus received a much needed addition to their interior illumination. It
is not surprising, therefore, to find many of the more daring Romanesque
builders including this central feature even in crossings with domes, as
has already been noted. As a rule the pendentives were introduced
beneath the wall of the clerestory drum which was therefore either of
octagonal or circular plan. The examples of such lanterns are too
numerous to cite though certain of them are worthy of some remark. In
Auvergne, for example, in Notre Dame-du-Port at Clermont-Ferrand (Figs.
49, 50), at Orcival (Puy-de-Dôme),[313] Saint Nectaire
(Puy-de-Dôme),[314] and elsewhere the system of transept and crossing
vaulting already described[315] made possible the introduction of
windows in either the east or west walls of the central towers, or both,
though rarely in those to the north or the south, where there were half
or full tunnel vaults to abut the dome. In two churches of Central
France, those at Bénévent-l’Abbaye (Creuse)[316] and Le Dorat (Haute
Vienne),[317] the lanterns are especially beautiful. They are covered
with domes raised on a drum supported upon spherical pendentives. In
such churches, where there is no direct light in the nave, the lantern
adds much to the appearance of an otherwise oppressively dark interior.
RIBBED DOMES
Another lantern of interest is to be seen in southern France in the
cathedral of Notre Dame-des-Doms at Avignon (probably cir. middle of
twelfth century).[318] Here the transepts are narrower than the nave and
in order to make the crossing square, a series of four arches has been
thrown across between the spandrels of the nave and choir arches, Over
the square thus formed is an octagonal lantern on squinches which in
turn supports a circular dome with the unusual feature of a series of
flat pilaster-like ribs along its-under surface. Such ribs are, of
course, largely decorative and correspond to those found in the apses of
many neighboring churches.[319] True ribbed domes were also used as a
means of covering the crossing,[320] and this is but natural in view of
the fact that such domes were quite frequently employed over circular
churches, as for example Saint Sepulchre at Cambridge, and the Templar’s
Chapel at Laon (Fig. 55),[321] while half domes of similar character
appear over many apses of the Transitional period.[322]
[Illustration: FIG. 55.--LAON, CHURCH OF THE TEMPLARS.]
LOBED DOMES
Similar domes to that just described at Avignon are quite common in
Spain, where for that matter the lantern itself had a very remarkable
development. Thus in the cathedral of Zamora (consecrated 1144) there is
a dome with sixteen ribs. It is not of perfectly simple type, however,
for the masonry between the ribs is curved slightly outward, giving it
the form of a lobed dome.[323] The lobes are comparatively small, but
otherwise not unlike such larger ones as those in SS. Sergius and
Bacchus at Constantinople (cir. 527) and the Serapeum of the Villa
Adriana at Tivoli (125-135). As far as construction is concerned this
arrangement made it possible to lay up the masonry between the ribs with
little or no centering, so that once the ribs were in place, the task of
completing the dome was a comparatively simple one. Unlike the “Gothic
dome” which is later discussed, the thrusts were not materially
decreased by the lobed plan and in its essentials the dome thus formed
was precisely like the simple type. From the point of view of appearance
these Spanish lanterns are certainly very beautiful. Usually pierced
with windows in twelve out of the sixteen bays, and sometimes, as at
Salamanca, with a few windows in the lower of the two stages forming the
drum, they admit a great quantity of light to the very heart of the
church where its presence is most needed. Moreover, the spherical
pendentives from which the lanterns rise are more pleasing than the
squinches generally found in France.
“GOTHIC DOMES” OR DOUBLE CHEVETS
Because of its resemblance to such ribbed domes as those just described
it may be well to discuss here what may be called a “Gothic dome” if
such a term be permissible. This is, in other words, the familiar chevet
vault extended to cover a space of circular or octagonal plan. One of
these vaults of circular plan and with eight ribs appears over the
crossing of Saint Nicolas at Blois (Fig. 56). Unlike the ribbed dome,
its masonry courses are not horizontal and concentric with the impost
line, but practically at right angles to it, thus giving wall arches
whose crowns are nearly as high as the central keystone itself. Each
window cell is thus precisely like one-quarter of a four-part
cross-ribbed vault. It was this form of double chevet vault which was
frequently used as late as the Renaissance period in Italy, where it
appears in such works as the Pazzi chapel at Florence (cir. 1420) (Fig.
57) and elsewhere though without
[Illustration: FIG. 56.--BLOIS, SAINT NICHOLAS.]
[Illustration: FIG. 57.--FLORENCE, PAZZI CHAPEL.]
[Illustration: FIG. 58.--WORMS, CATHEDRAL.]
any wall rib. These “Gothic domes” were frequently polygonal as well as
circular. Thus in the cathedral of Worms (Fig. 58) there is an octagonal
lantern, on squinches, surmounted by a vault with eight cells of
decidedly domical type, the whole being only slightly different from a
lobed dome. A more developed double chevet, dating from the second half
of the fifteenth century, appears over the crossing of the cathedral of
Evreux (Eure),[324] where there is also a complete system of ribs.[325]
The form of the pendentives is that of flat triangles, and they are
decorated with elaborate designs in flamboyant tracery. Similar flat
triangles but with a series of mouldings at the top, are used to support
the octagonal lantern of Coutances cathedral (Fig. 59), perhaps the most
beautiful in France, and apparently dating from the second half of the
thirteenth century. Its vault is in sixteen cells, two to each lantern
wall, and each containing a lofty window, the whole clerestory rising
above a lower stage of coupled arches with a narrow passage behind them.
[Illustration: FIG. 59.--COUTANCES, CATHEDRAL.]
A crossing vault of similar character, but with a change in the
arrangement of the ribs, which form an eight-pointed star around a
central octagonal opening, is to be seen in the cathedral of Saragossa
in Spain (after 1500),[326] while the final stage in such vaulting, in
which the ribs become merely a framework beneath a flat ceiling, but
nevertheless a framework of elaborate and beautiful design, may be seen
over the crossing of the cathedral of Burgos (finished 1568).[327]
SQUARE LANTERNS WITH EIGHT-PART VAULTS
There now remain for discussion lantern towers of square plan. This was
the form almost universally employed in Normandy, England, and churches
which came under Norman influence, especially in the earlier Gothic
period. During the Romanesque epoch such lanterns were wooden roofed.
But with the introduction of the ribbed vault, an eight-part vault was
devised for this crossing, whose severies were precisely like those
above the windows in six-part vaulting, from which, in fact, this new
type probably developed.
Most of the towers originally wooden roofed have since been vaulted, and
it is therefore difficult to judge of their original character. Their
imposing interior appearance, however, may be judged from the ruins of
the abbey church of Jumièges (1040-1067). It would seem, from the places
for beam ends left in the wall, that such lanterns as this were
generally roofed with a flat ceiling above the first stage of openings,
the second series probably forming a belfry. It is natural, therefore,
when vaulting comes in, to find it placed at the level of the former
flat ceiling with only the lower openings used as windows, leaving the
walls above to offset the thrusts of the vault by their downward
pressure. A somewhat rudimentary vault of this eight-part character may
be seen in Saint Georges-de-Boscherville,[328] in which the wall arches
are omitted and all the ribs made to spring from corbels. This, of
course, is because the Norman Romanesque crossings were not originally
planned for vaulting. A little later, wall ribs were regularly used, and
in Saint Yved at Braisne (consecrated 1215)[329] the four major ribs
have their supports running all the way to the floor, while in the
cathedral of Laon (after 1165) (Fig. 60) even the eight wall ribs which
rise from the corners of the tower are similarly carried down. Of course
the intermediate ribs necessarily rise from corbels, but in the
developed crossings of this type such corbels are placed as near as
possible to the crowns of the four great arches of the nave, choir, and
transepts. Similar lanterns are to be seen in the church of Notre Dame
at Cluny, and in Saint Maclou at Rouen (lantern cir. 1511),[330] where,
however, ridge ribs are added in each of the eight cells.
Notwithstanding the examples cited, the use of a lantern is not common
in developed Gothic architecture. This is perhaps due to the fact that
the rapidly increasing size of the clerestory made such an addition to
the lighting equipment unnecessary, though it is more probable that the
great height of many of the churches rendered the construction of a
tower over the crossing a dangerous undertaking. Even in the less lofty
churches of England, where a central tower is almost invariably found,
the latter is frequently closed from below by a vault.
RIB-VAULTED CROSSINGS WITH NO LANTERNS
[Illustration: FIG. 60.--LAON, CATHEDRAL.]
Where there is no lantern, the vault of the crossing is generally a
continuation of that of the nave or transepts. It is, therefore, often
of simple four-part cross-ribbed type, with or without a domed up
crown.[331] Certain of the Gothic builders, however, even in the early
thirteenth century, realized the advantage to be gained by subdividing
the cells of the crossing vault with ridge ribs. Hence in the abbey
church of Fossanova (consecrated in 1208),[332] as well as in those at
Casamari and Arbona[333] in Italy, and in many churches of France,[334]
especially those of Anjou type,[335] transverse and longitudinal ridge
ribs were used and in most instances the vault was considerably domed
up. In Amiens cathedral (cir. 1265) the crossing vault, nearly forty
feet square and about one hundred and forty feet from the ground, was
further subdivided by a single pair of tiercerons in each of the major
severies, and the eight central panels thus formed were raised at the
crown to reduce the thrusts of the vault as well as the amount of
centering necessary for its construction. After its introduction at
Amiens this form of crossing was quite extensively employed, sometimes
with its ridge ribs running completely across the bay, as for example,
in Auxerre cathedral, sometimes running only to the keystone of the
tiercerons, as in Bayonne and Troyes cathedrals or Saint Euverte at
Orleans.
With the use of many added ribs in other portions of the church, came a
corresponding elaboration in the vaults of the crossing. Thus many
examples might be cited of lierne and tierceron vaulting in all degrees
of complexity, especially in England,[336] while fan vaulting is to be
seen in the abbey church of Bath (cir. 1500-1590),[337] and pendant
vaults of elaborate character in Saint Étienne-du-Mont at Paris
(probably cir. 1550-1600). Occasionally also the transept is subdivided
by a central row of piers in which case the vault of the crossing is in
two bays.[338] It is unnecessary, however, to discuss at length these
exceptional crossing types since they do not differ structurally from
the vaulting systems already described in connection with the nave.