Edifici per animali di età romana: tra fonti, archeologia e scienza/ Roman buildings for animals: between sources, archeology and science

The identification of buildings used for housing animals is problematic because of the scarce planimetric characterization, the perishable structures, the rare discovery of indicators of activity. The latin writers de re rustica and Vitruvius provide helpful descriptions, but rarely decisive: for the cattle (bubile), stables close to the kitchen, south-facing (Colum. 1.6), wide 10 to 15 roman feet (3.00-4,50 m) (Vitr. 6,6,2), equipped with feeders (Colum. 1,6,7); for the sheep, low sheepfolds (humilia stabula), longer than they are wide, south-facing (Colum. 7,3,8), with wide doorways; also for the horses (equile) the latin authors suggest to set stables in warm place (Cat. 14.2; Vitr. 6.6; Var. 2,7,14; Colum. 6.27), to put in praesepia to keep the animals separated (Var. 2,7,7; Col. 6:27), to get the floor paved and declining to keep it clean and dry (bubile: Var. 2, 5, 16; Col. 6, 23; ovile: Var. 2, 2, 19, 2, 3, 6; Col. 7, 4, 4; equile: Col. 6:30). The framework provided by the archaeological record is therefore very poor: a stable is generally assumed in case of large dimension, long shape, south-facing buildings, especially if they are equipped with small channels. Instead, scientific analysis (biological, chemical) may have a significant role. The most reliable indicators are the organic and bioinorganic remains (coprolites, spherulites, phytoliths), which sometimes enable to distinguish which kind of animal was bred; unfortunately, these elements are preserved in particular conditions, rarely in open air contexts. Among the Roman stabula identified through typology of phytoliths there are the famous “bergeries” excavated in 1989-1990 in the Crau Arles (Gaul Narbonne, Ist century BC-IVth century AD). In case of exposed archaeological site, chemical analysis of soil can also be helpful since it retains in depth traces of anthropogenic use, including the prolonged presence of animals. Thanks to these analysis, some Roman farms excavated in the Altinum area (north Venice lagoon, Italy, Ist century-Vth century AD) were recognized as stables and sheepfolds. The farms included big squared (12 x 12 m) or rectangular (33 x 9 m) structures, separate from the main building; no evidence of a prepared floor has been detected; the walls were at least partially made of wood, suggesting a minor architecture: the hypothesis is that they could have been enclosures or stables for bred animals. Therefore the problem we are dealing with is the chance of recognizing the archeological traces of ancient animal husbandry. Analyses of the phosphorus (P), carbon (C) and nitrogen (N) content of the soil, together with elemental ratios, were applied to the structures. Two different methods, ignition (i) and hydrolysis with perchloric acid (h) were used to determine the total P (TP) content and their reliability is discussed. Results showed very high values in both iTP and hTP in the site. High inorganic P (IP) contents were found just along the walls of the building giving evidence for the mineralization of organic P (OP) which was entrapped into inorganic with the calcium carbonate and thus preserved. Among the elemental ratios, the organic C/total C (OC/TC) and C/N highlighted for a organic matter from animal and not from vegetable origin, whereas the OC/OP and N/OP confirmed for the anthropogenic origin of the site. All these results strongly support for the identification of the remains of Roman rural building as stables for bred cattle or as sheepfolds. Archaeozoological studies suggested what kind of farming was practiced at Cà Tron, although they suffered the bad state of conservation of the samples and the poorness of reliable stratigraphic data, so that it is difficult, in these studied case, to establish a relationship between the out-buildings and the archaeozoological data; nevertheless, they documented, for the farm A, the presence of cattle, pigs and sheep, therefore a integrated economy, which guaranteed the practice both of agriculture and breeding, for the farm M, a high predominance of sheep, attesting the practice of a intensive sheep breeding, probably the delicatissimae oves named by Pliny the Younger in a famous letter (epist. 2, 11, 25).