LAUSR

Abstract We report on ceramic and glaze chemical and technological data on lead-glazed redware pottery, sampled from late medieval, ca. 14th–17th century CE contexts at five sites across the Gulf of Finland, in modern Finland and Estonia. Redware pots first arrived in this region as Scandinavian and Continental imports, and their local manufacture was established in the 15th–16th centuries. We aimed to chemically characterize ceramic and glaze recipes, distinguish between local and imported redware pots at the sites, and to examine glaze preparation and application practices used. Altogether 34 sherds of ceramic artefacts from three hamlet sites in the Helsinki region (Gubbacka, Mankby and Martensby), and the towns of Turku and Tallinn were geochemically and microstructurally analysed by energy-dispersive X-ray fluorescence spectrometry (ED-XRF) and scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS). The majority of the analysed pots were made of clay originating from the Gulf of Finland region, produced at least in Turku and highly likely in Tallinn. Redware was also exchanged between these trading areas. High-lead-content (PbO