A multi-technique study for the spectroscopic characterization of the ceramics from Santa Maria do Castelo church (Torres Novas, Portugal)

An excavation in a 14th c. church at Torres Novas, named Santa Maria do Castelo, provided some green glazed ceramic sherds, archaeologically dated from 14th c. to the 16th c. The town of Torres Novas is located at the center of Portugal, about 100 km north of Lisbon. The obtained results evidence three types of pastes of the pottery: type 1 with Quartz, Illite, Muscovite and Microcline as the main constituents, type 2 with Quartz, Calcite and Gehlenite; and finally type 3 with Quartz, Calcite and Diopside being the major components. Type 1 pastes are related to clay sources of Pliocene origin, and all this pottery was most probably made in Portuguese kilns. However, types 2 and 3 spectroscopic trends are remarkably different, indicating that those ceramics were produced in Seville. All the studied ceramics are lead glazed, and green glazed. In one of the samples from the Seville kiln, Cerusite was the main pigment used to obtain the greenish colouration. In what regards the origin of all samples produced with Pliocene clays, the 16th c. ones were most likely produced in the Santo Antonio da Charneca or Mata da Machada kilns, both located in the south shore of the Tagus river, region of Lisbon. In what regards the green glazed jug rim (14th c.) and the jug spout (15th c.) they could also have been produced in the two mentioned kilns south of Lisbon city, but another interesting hypothesis - due to richness of the decoration - is the production in Lisbon workshops, with the use of Pliocene clays imported by Lisbon potters, now documented both in Lisbon archaeological findings and also in documental sources.