requirement—lighting. Due to the great outward thrust barrel vaults
exert along their full length, even when pointed instead of semicircular,
a clerestory is difficult to construct. (The Santiago de Compostela,
Toulouse, and Fontenay designers did not even attempt to introduce a
clerestory, although their counterparts at Cluny III did and succeeded.)
Structurally, the central aim of northern Romanesque architects was to
develop a masonry vault system that admitted light and was also aes-
thetically pleasing.
Covering the nave with groin vaults instead of barrel vaults be-
came the solution. Ancient Roman builders had used the groin vault
widely, because they realized that its concentration of thrusts at four
supporting points permitted clerestory windows (FIGS. 10-6b–c,
10-67,and 10-78). The great Roman vaults were made possible by
the use of concrete, which could be poured into forms, where it so-
lidified into a homogeneous mass (see “Roman Concrete Construc-
tion,” Chapter 10, page 241). But the technique of mixing concrete
had not survived into the Middle Ages. The technical problems of
building groin vaults of cut stone and heavy rubble, which had very
little cohesive quality, at first limited their use to the covering of
small areas, such as the individual bays of the aisles of Saint-Sernin
(FIG. 17-5). But during the 11th century, masons in the Holy Roman
Empire, using cut-stone blocks joined by mortar, developed a groin
vault of monumental dimensions.
SPEYER CATHEDRAL Construction of Speyer Cathedral
(FIG. 17-19) in the German Rhineland, far from the pilgrimage
routes of southern France and northern Spain, began in 1030. The
church was the burial place of the Holy Roman emperors until the
beginning of the 12th century, and funding for the building cam-
paign came from imperial patrons, not traveling pilgrims and local
landowners. Like all cathedrals,Speyer was also the seat (cathedra in
Latin) of the powerful local bishop. In its earliest form, Speyer Cathe-
dral was a timber-roofed structure. When the emperor Henry IV
(r. 1084–1105) rebuilt it between 1082 and 1105, his masons covered
the nave with stone groin vaults. The large clerestory windows above
the nave arcade provided ample light to the interior. Scholars disagree
about where the first comprehensive use of groin vaulting occurred
in Romanesque times, and nationalistic concerns sometimes color
the debate. But no one doubts that the large groin vaults covering the
nave of Speyer Cathedral represent one of the most daring and suc-
cessful engineering experiments of the time. The nave is 45 feet wide,
and the crowns of the vaults are 107 feet above the floor.
Speyer Cathedral employs an alternate-support system in the
nave, as in the Ottonian churches of Saint Cyriakus (FIG. 16-21) at
Gernrode and Saint Michael’s (FIG. 16-23) at Hildesheim. At Speyer,
however, the alternation continues all the way up into the vaults,
with the nave’s more richly molded compound piers marking the446 Chapter 17 ROMANESQUE EUROPE17-19Interior of Speyer Cathedral, Speyer, Germany, begun 1030;
nave vaults, ca. 1082–1105.
The imperial cathedral at Speyer is one of the earliest examples of the
use of groin vaulting in a nave. Groin vaults made possible the insertion
of large clerestory windows above the nave arcade.17-20Aerial view of Sant’Ambrogio, Milan, Italy, late 11th to early
12th century.
With its atrium and low, broad proportions, Sant’Ambrogio recalls Early
Christian basilicas. Over the nave’s east end, however, is an octagonal
tower that resembles Ottonian crossing towers.