Maintenance of Underground Granaries in Medieval Towns; Case Study from Padowetz, Brno, Czech Republic

Medieval underground granaries are typical storage facilities for the Slavic part of Europe, but their appearance generally all over Europe is not limited to just a few regions. Though typical for the rural environment of villages, these objects are nearly unknown in cities. The only examples excavated inside city walls belong to the 12th to 14th century. This also explains why the maintenance practices used are nearly unknown. The Medieval granary excavated inside the city walls of Brno, Czech Republic, has provided important information concerning the way the granary was maintained and used. Micromorphological descriptions, combined with the PRTG analyses, show that the excavated granary was probably used repeatedly. The walls of the granary and also its bottom had been repeatedly sealed with straw. This material was at the bottom of the infill preserved in a nearly fresh state or totally impregnated by phosphates. Also the phases of bioturbation and the record of a burning event were recorded. The burning of the interior parts of the granary was probably their way of cleaning. The temperature was not higher than 300̊ C. These practices may be compared with rural practices documented already in 18th century in village areas. This is the first documentation of the processes of maintenance for Medieval granaries as compared with more recently documented practices. It confirms that the local inhabitants of a Medieval town applied the older rural tradition as known from village areas. IANSA 2017 ● VIII/2 ● 157–165 Lenka Lisá, Marek Peška, David Merta, Miloš Gregor: Maintenance of Underground Granaries in Medieval Towns; Case Study from Padowetz, Brno, Czech Republic 158 (Procházka 2012, 1012; 2013). Generally the underground granaries are often pear-shaped, with small openings and diameters of up to three metres at their widest point (Kunz 2004). The underground granaries excavated up till now in the Brno town area are usually pear-shaped with diameters of 1.8 m (2.2 m respectively) reaching a depth of 3.6 metres. These have been detected mainly in the distal parts of burgher plots (Kobližná 3, Josefská 8, Starobrněnská 18; Procházka 2013, 110; 2012, 203; 2000, 58). Due to the fact that most of the plots demarcated in the second quarter of the 13th century do not show any underground granary locations, we can connect their appearance mainly with the older rural tradition of the local inhabitants. While the need for cereals in the towns lasted, unlike in the villages there was no need to store added cereals for sowing. Additionally there was the need to store not only cereals, but also craft and other raw materials. The urban character of the sunken features at that time was usually already connected with the construction of earthen house cellars (Holub et al. 2005). The storage of the ceramic vessels (Nekuda, Reichertová 1968, 63; Procházka, Peška 2007, 168) used to store cereals had in fact replaced the need for underground granaries. To preserve the grain in an anaerobic environment, the pits were filled to the top and then hermetically sealed. The oxygen remaining in the silo would alter (decompose) the grain in contact with the earthen walls, but would be quickly used up as it turned to carbon dioxide. Cereals could thus be kept for several years without fermenting and without being attacked by insects. Among all these silos, certain cylindrical pits may be distinguished by their greater depth and by the existence of internal compartments associated with a raised floor. This arrangement solved the problem of excess humidity by creating an opening for coals or heated stones to be introduced, thus drying out the silo’s contents. We know that a part of the stored grain was thus steamed or grilled. These pits, which were normally grouped together a short distance from dwellings, were no doubt used to store excess grain from the harvest. After a period of use – which we believe to be relatively short – these silos were often converted into waste pits (Kunz 2004). There is a little known about the maintenance of underground granaries from the 12th–14th century, especially in the town environment of the city of Brno. The main aim of this paper is therefore an evaluation of the possible maintenance methods of the underground granary excavated at the edge of the Brno medieval burger plot, and the information value of such sedimentary records for understanding the medieval practices of these storage pits. 2. Material and methods The construction of an underground parking area for the Padowetz Hotel in 2008 (Bašty Street No. 2), was the Figure 1. Location of the study area together with the plan of the excavations and a section of the underground granary. 1) Bašty street No. 2; 2) Josefská street No. 8; 3) Starobrněnská street No. 18; 4) Kobližná street No. 3. 0 5 m IANSA 2017 ● VIII/2 ● 157–165 Lenka Lisá, Marek Peška, David Merta, Miloš Gregor: Maintenance of Underground Granaries in Medieval Towns; Case Study from Padowetz, Brno, Czech Republic 159 reason for the rescue excavations led by the archaeological company Archaia Brno. The study area, at an altitude of 214 m a.s.l., was located in the internal part of plot 351, Bašty Street, on the gentle lower slopes of the Petrov Hill. This area belongs historically to the medieval quarter of Brno town (Quartale Brunensis), in the close neighbourhood of the city walls and Jewish gateway (Porta Judeorum). The excavated area had the dimensions of 18×13 m. The geological background was composed of loess with a partlypreserved soil cover (20–30 cm). There were the preserved foundations of two houses, two ovens and one underground storage pit interpreted as an underground granary (Figure 1). The infill of the granary was quite homogenous with a laminated bottom part. This part was described according to field sedimentological criteria, based on parameters such as colour, texture, and internal organization. The colour of the sediments was identified in both a wet and dry state using a Munsell soil colour chart. The two micromorphological Figure 2. Documentation of the underground granary from Bašty Street together with a detail of the laminated bottom of this granary. 0 1 m IANSA 2017 ● VIII/2 ● 157–165 Lenka Lisá, Marek Peška, David Merta, Miloš Gregor: Maintenance of Underground Granaries in Medieval Towns; Case Study from Padowetz, Brno, Czech Republic 160 samples from this layer were collected using a Kubiena box. Large thin sections (approximately 140×70 mm) were prepared in the laboratory of Julie Boreham, Reach, GB (www.earthslides.com) and examined under plain and cross polarised light at different magnifications (40–800×). The descriptions and interpretations mainly followed the guidelines used by Stoops (2003) and Stoops et al. (2010). The mineralogical composition of the black uppermost part of the laminated fill of the granary was estimated with help of X-ray powder diffraction analyses using Bruker D-8 Advance (Department of Mineralogy and Petrology, Comenius University, Bratislava) operating at 440 kV and 40 mA using Cu antikathod (Cukα1=Å) and a Ni filter. The can speed recording intensities was in 0.01 °2θ per 1 second and oriented powder specimens were prepared.