Budapest Régiségei 30. (1993)

TÁRGYI EMLÉKEK ÉS LELETEK = DENKMÄLER UND FUNDE - Madarassy Orsolya: Tabula gromatici az aquincumi canabaeból 297-315

TABULA GROMATICI FROM THE CANABAE OF AQUINCUM During 1989-1991 research was carried out at lots 3 to 11 on Pacsirtamező street, in Budapest's Illrd district. This area corresponds to the surroundings of the amphitheatrum that belonged to the canabae located around the Aquincum legionary fortress. An approximately fifty meter long section of the Roman street leading from the limes road to the amphitheatrum was excavated together with the rows of tabernae that lay north and south of this connecting road. The back sides of a few buildings along the limes road were also uncovered. This area was continuously developed beginning in the second half of the 1st century until the second half of the 3rd century. As a consequence of late 3rd and early 4th century army reforms, however, the area was gradually abandoned. By the 4th century it served as burial grounds. It is this site that a bifacial, inscribed marble fragment with chiseled concentric patterns was discovered during the autumn of 1990. This find came to light when the relatively late wall foundations of the northern taberna were excavated. Stratigraphically, this object may be attributed to both the stone material used in laying the foundations of this 3rd century wall and the 2nd century levelling out layers found at the bottom of the foundation ditch. These strata associated with levelling that preceded drainage work, also contained artifactual material from previous buildings that had stood there at the turn of the 1st and 2nd centuries. The marble object itself was described in detail by Ferenc Noéh in this volume. This technical artifact can be interpreted only on the basis of an exact technical description using phylological methods founded on the critical evaluation of sources. On the basis of these considerations, the characteristics of this object will be listed in the logical sequence of interpretation. Nine concentric, equidistant half circles originating from the same line were may be found on side "B" of this artifact. These arches are divided into segments by short, oblique and bent incisions which follow a regular pattern. Within the innermost half circle, left of the straight line, a letter D may be found. The beginnings of half circles are labelled by four city names: SUENIS/ALEXA/RODO/ATHE (Photo 1). On side „A" fragments of two, similarly concentric half circles appear as well as the remains of another circle which was divided into 90 sections by two rectangular, straight lines. Radii originate from the center of this circle which are connected by additional circle segments divided by one and eight short, radially located incisions respectively. Two markings outside the outermost circle include the label X C and a fragmentary .XXX sign (Photo 2). In addition to these original set of designs, vague, use-related incisions also occur on this object. These include two arches as well as a straight line, this latter running across the centre of the basic circle (Photo 3). The city names suggest that the function of this object was related to geography while the arches and angles indicate that the object may have been used within the realm of mathematics. The outermost angle measured on side „A" measures 23,5° to 24° which corresponds to the ecliptic angle. This may be suggestive of an astronommic approach. Should a straight object have been placed in the centre of the circular pattern, its shadow might also permit the interpretation of this artifact as a sun dial. Since the majority of natural and technical sciences formed a global entity during Antiquity, multiple hypotheses concerning the function of the objects do not exclude but rather support each other. It seems certain that this must be the fragment of a Roman engineering instrument which was not made in Pannónia but was used here. The fragment of this broken artifact may have been deposited anytime during the 1st and 3rd centuries. Since, however, it was buried in the military town of the legionary fortress, this artifact may, in all likelihood, be related to military activities. It may be assumed that the instrument belonged to the equipment of an engineer (gromaticus) in the legion's engineering unit. Since the time span between this instrument's import to Aquincum and its deposition can be estimated only in relative terms, its more accurate dating and functional identification may be further facilitated by considering the prevailing technical, geographical and astronomical view of the world characteristic of the discussed period in Antiquity. At the beginning of Georaphica Hypomnemata, Strabo summarized the up-to-date scientific knowledge of the „Augustian Golden Age". Without providing a detailed, thematic list of data in scientific history, a few axioms should be pinpointed. These undoubtedly belonged to the general body of knowledge of the earliest Roman professionals who came to Aquincum. 1) The Earth was divided into belts. The two sides of the Equator were accompanied by the tropical climate belt which was defined by the two tropics. Beyond the tropics, the temperate climate belt extended to the arctic/antarctic circles. Finally the remaining, circumpolar area was considered the cold belt. The southern shadow on a sun dial goes around above the arctic circle, this is why these two belts were called „shaded around" (periskion); In the temperate belt the shadow points either to the south or the north, always on the „opposite side" (heteroskion). In the tropical zone, the shadow alternates between south and north, depending on the actual position of the Sun. There301