The Plan of St. Gall :: :: University of Virginia Library

The heating system of the Monks' Warming Room raises
interesting historical and technological questions. It consists,
as already pointed out, of an external firing chamber
(caminus ad calefaciendū) that transmits its heat to the
building through heat ducts (not shown on the Plan), the
necessary draft for which is generated by an external smoke
stack (euaporatio fumi).

Identical heating units appear in two other places on the
Plan, the "warming room" (pisale) of the Novitiate and
the "warming room" (pisale) of the Infirmary.[58] Keller's[59]
attempt to interpret these devices as simple fireplaces is
untenable and was convincingly repudiated by Willis.[60]
They are clearly descendants of the Roman hypocaust
system. The existence of such heating systems in the
Middle Ages is well attested both by literary and archeological
sources. A hypocausterium almost contemporary with
those of the Plan of St. Gall was built by Abbot Ewerardus
at the monastery of Freckenhorst.[61] An excavation conducted
in 1939 at Pfalz Werla, one of the fortified places of

254

[ILLUSTRATION]

201. LORSCH, MONASTERY OF ABBOT RICHBOLD (784-804). ISOMETRIC RECONSTRUCTION

[after Selzer, 1965, 148]

The abbey grounds, of irregular ovoid shape, were surrounded by a masonry wall. Entering the monastery from the west the visitor stepped into
a large rectangular atrium where he had to pass through what can only be called the Carolingian equivalent of a Roman triumphal arch
accommodating over its passages a small royal hall (a jewel of Carolingian architecture, built 768-774, the earliest wholly preserved building of
post-Roman times on German soil). At the end of this atrium the visitor faced two massive towers flanking a gate that gave access to a second,
considerably smaller atrium lying before the monumental westwork of the church of St. Nazarius, an aisled basilica with low transept and
probably a rectangular choir, built between 767-774, and enlarged eastward in 876 by a crypt for royalty. The component building masses of
this architectural complex rose in dramatic ascent on successively higher levels of the gently rising slope of a natural sand dune; the west gate at
the bottom, the choir of the church at the top, the late Carolingian crypt eight meters below the level of the church on the steeply descending
east slope of the dune.

The walls of the monastery enclosed an area of roughly 25,000 square meters. Forming a veritable VIA SACRA, from gate to altar the route of
passage was nearly 260m. long.

255

[ILLUSTRATION]

LORSCH, MONASTERY OF ABBOT RICHBOLD (784-804).

200.X

200.

12TH-CENTURY PLAN AND ISOMETRIC VIEW

Fig. 200: after Behn, 1964, 117; Fig. 200.X: after Hubert, Porcher, Volbach, 1970, fig. 377.B]

Toward the middle of the 12th century, the inner Carolingian atrium was converted into a fore church. At the same time, all the claustral
ranges were rebuilt on the foundations of their Carolingian predecessors. (For remains of the latter see Vorromanische Kirchenbauten,
1966, 180).

Henry I of Saxony, tells us much about the details of construction
of such a hypocausterium. There, beneath a hall
constructed between 920 and 930, C. H. Seebach unearthed
a hypocaust in an excellent state of preservation.[62]
Its heating plant (fig. 209) consisted of a subterranean
firing chamber beneath the floor of the hall, which was
reached by an outside passageway. A system of radiant
ducts channeled the heated air from the firing chamber
into a circular flue which lay directly under the pavement
of the hall and was provided, at regular intervals, with
tubular vents through which the warmth ascended into
the hall above. Another large flue ran from this main duct
to the western gable wall where it emptied into a smoke
stack. This flue showed heavy traces of blackening, which
suggests that the hot air outlets into the hall could be
closed by stone lids during the initial firing stages, when
the volume of smoke and obnoxious gas was heaviest,
leaving the chimney as the only outlet.

Seebach believes that the hypocaust system of St. Gall
was identical with that of Werla. However, the two
systems are not alike in every detail. The Werla firing
chamber lay beneath the hall; the firing chambers of St.
Gall are external attachments. They must have been subterranean,
of course, for otherwise the heated air could not
rise into the hall above, but the general principle of construction
was doubtlessly the same, and the occurrence of
this type on the Plan of St. Gall is clear testimony that

256

[ILLUSTRATION]

202. SILCHESTER, HAMPSHIRE, ENGLAND, ROMAN BASILICA AND FORUM

PLAN (after Joyce, 1887, pl. 16)

A provincial variant of a distinguished lineage of Roman market halls, Silchester is related to the basilicas of Trajan in Rome (fig. 239) and
Septimius Severus in Lepcis Magna (fig. 159). To students considering history as a chronological progression, the similarity of layout of these
Roman market halls with that of the Carolingian CLAUSTRUM is perplexing. Yet such a conceptual leap into the classical past may be even
more easily understood than the Carolingian revival of the Constantinian transept basilica. To study the layout of the latter, Frankish
churchmen had to travel to Rome, but they could see surviving or ruinous examples of the Roman market hall in their homeland. Basilicas of
the Silchester type existed in the Roman city of Augst in Switzerland (Reinle, 1965, 34) and in Worms, Germany. The latter was well known
to builders of the Merovingian cathedral of Worms (Fuhrer zu vor-und frühgeschichtlichen Denkmälern, XIII, 1969, 36).

257

[ILLUSTRATION]

203. PLAN OF ST. GALL. CLOISTER YARD

Although in plan displaying striking similarities with the great galleried courts of the Roman market halls (cf. figs. 202, 239) the four-cornered
medieval cloister shows marked differences in elevation (cf. fig. 192). The Roman basilican courts are vast areas for open-air assembly and
the conduct of business, surrounded by relatively small offices and shops of modest height (fig. 202). The open yard of a medieval cloister, by
contrast is small in relation to the buildings by which it is enclosed. The latter rise high and are surmounted by steep-pitched roofs. Internally,
although composed of two levels, they form open halls extending the entire length of the building. The galleried porches are the only connecting
links between these huge structures, none of which possess interconnecting doors or entrances. The tint block on the opposite page shows the above
cloister (100 feet square) at the scale of the Silchester basilica (1:600).

258

[ILLUSTRATION]

204. DIOSCURIDES. MATERIA MEDICA

Vienna, National Library, CODEX VINDOBONENSIS, fol. 48v

SAVIN PLANT (JUNIPERUS SABINA)

[by courtesy of the National Library of Vienna]

Pedanios Dioscurides of Anazarbos, a physician of Greek descent
who served in the army of Nero, wrote his Materia Medica around
50 A.D. It details the properties of about 600 medicinal plants and
describes animal products of dietetic and medicinal value. The writing
of Dioscurides was well known and widely read in the Middle Ages
and served as a standard text for learning in all medical schools.
The illustration shown above is from a richly (in places even
brilliantly and very realistically) illuminated copy of this treatise
executed by a Byzantine artist in 512, and now available in a
magnificent facsimile edition.

hypocausts with a complete system of heat-distributing air
ducts, and a chimney stack for draft and evacuation of
obnoxious gas were, at the time of Louis the Pious, a
standard system used in the construction of monastic
warming rooms. Whether or not the heat produced by this
system could also be conducted into the Dormitory above
remains a moot question.

[58]

See below, pp. 311ff (Novitiate) and 313 (Infirmary).

[59]

Keller, 1844, 21.

[60]

Willis, 1848, 100.

[61]

Nec ab incoepto destitit donec in circuitu oratorii refectorium hiemale et
aestivale, hypocaustorium, cellarium, domum areatum, coquinam, granarium et
dormitorum, et omnia necessaria habitacula aedificavit." (Vita S. Thiadildis
abbatissae Freckenhorsti; see Schlosser, 1896, 86, No. 283). For previous
discussions of the hypocausts of St. Gall see Keller, 1844, 21; Willis,
1848, 91; Stephani II, 1903, 77-83; Oelmann, 1923/24, 216.

[62]

Seebach, 1941, 256-73. The remains of the channels and a freestanding
chimney of the hypocaust which heated the calefactory and the
scriptorium of the Abbey of Reichenau, built at the time of Abbot Haito
(806-823), were excavated by Emil Reisser in the immediate vicinity of
the nothern transept arm of the Church of St. Mary's at Mittelzell
(see Reisser, 1960, 38ff). For other medieval calefactories with hypocausts,
see the article "Calefactorium" by Konrad Hecht in Otto
Schmidt, Reallexikon zur Deutschen Kunstgeschichte, III, 1954, cols.
308-12; and Fusch, 1910.