Misconceptions about the "displuviate" and
"testudinate" Roman courtyard house
Julius von Schlosser[10]
tried to overcome this weakness by
demonstrating that Rahn's St. Gall house was historically
the descendant of a once widespread Roman house type to
which the ancients referred with the terms "displuviate"
(displuviatum) and "testudinate" (testudinatum). Schlosser's
theory, unfortunately, was based on two erroneous assumptions
that were current in his day, which imparted to the
discussion of the design of the guest and service structures
of the Plan of St. Gall an element of further confusion.
The first of these misconceptions pertained to the precise
meaning of the terms "displuviate" and "testudinate";
the second concerned the origins and structural evolution
of the Roman atrium house.
To begin with the former: what Vitruvius and Varro
designated by the terms "displuviate" and "testudinate"
can under no circumstances be interpreted as structures
of basilican design. They were atrium houses in the full
constructional sense of the term, i.e., houses in which the
living quarters were ranged around an originally open
center space. The terms "Tuscan", "Corinthian", as well
as "tetrastyle", "displuviate", and "testudinate" (tuscanicum,
corinthium, tetrastylon, displuviatum, and testudinatum)
merely referred to the different degree or manner in which
these inner courtyards were roofed over.[11]
In the Tuscan
atrium house, for instance, the courtyard roof sloped down
toward the center (fig. 265); in the displuviate house it
sloped upward. But in both cases the courtyard roof
encompassed in its center a rainhole (compluvium) that had
under it not a hearth, but a catch basin (impluvium).
Schlosser did not realize that in connecting the St. Gall
house with the displuviate Roman atrium house, he had
actually retrogressed to Lenoir's views (fig. 265), whose
weakness Rahn's reconstruction (fig. 266) had already
successfully overcome.
The same applied to Schlosser's attempt to connect the
St. Gall house with the courtyard house referred to by
Vitruvius and Varro by the term "testudinate." It is an
atrium house like all the others, as must be inferred not
only from the language of the opening sentence with which
Vitruvius introduces his subject ("
Cava aedium quinque
generibus sunt distincta . . ."; "the inner courts of houses
are of five different styles," etc.), but also from the detailed
descriptions that follow ("
Testudinata vero ibi fiunt, ubi non
sunt impetus magni et in contignationibus supra spatiosae
redduntur habitationes . . ."; "Testudinate courtyards are
employed when the span is not great, and they furnish
roomy apartments in the story above").
[12]
In contradistinction
to the other four types in which the courtyard was only
partially roofed over, the testudinate atrium house was a
house in which the inner court was entirely covered. It was
an atrium house in which the courtyard had lost the character
of an open space by being covered over with a second
story, but it was still an atrium house.
[13]
The Romans used
this type of construction in houses of relatively small
dimensions, as Vitruvius himself suggests, and probably in
response to restricted land conditions prevailing in the
crowded Roman cities.