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CIRAM invited by V&A Museum for a conference about the Aghlabids

The metallic lustre decoration of the Mihrab of the great Mosque of Kairouan (Tunisia, 9th century AD). Scientific investigations.
Olivier Bobin1, Max Schvoerer2, Claude Ney2 

Friday 23 May - 12.15 - Winston House, 3 Bedford Square, London WC1B 3RA

1 CIRAM – 16 avenue Pey Berland, 33600 Pessac – France – Phone: 0033 (0)5 57 34 21 18
2 CRPAA IRAMAT – UMR 5060 – Université Bordeaux 3 / CNRS - 33607 Pessac - France

At the end of the 8th century, in Mesopotamia, some genius potters have discovered and improved a singular glazed ceramic decoration, so-called metallic lustre. It is a copper and silver based decoration, which requires an ultimate firing at low temperature (around 600°C) in reducing atmosphere. The metallic lustre is not a classic decoration, such as cobalt blue or iron yellow glaze. Its colour changes with the observation angle. In diffused reflection, it can be green, brown or yellow, and in specular reflection (mirror-like reflection of light) it shows a coloured metallic shine (blue, golden-yellow, orange). The metallic lustre is composed of copper and silver colloids (nanometric sphere), which give these specific optical properties.

One of the most beautiful examples of lustre decoration used in architecture is probably the mihrab of the Sidi Oqba mosque in Kairouan (832-863 AD, Tunisia). It is still covered with 161 "lustre tiles", which have two types of decoration: a monochromic green one and a polychromatic green, yellow and brown one.

From Medieval texts, it was established that the polychromatic tiles were made in Mesopotamia and the monochromatic tiles were made in Kairouan by a potter come from Baghdad. Several modern authors still use these conclusions, but the origin of the Kairouan tiles has never been scientifically established.

From the physicochemical analyses of several glazed tiles of Kairouan, we have characterised their technological features and we have compared them with those obtained on Mesopotamian and Tunisian artefacts. From these comparisons, we have established if the Kairouan lustre tiles were made in Mesopotamia or in Kairouan or in both locations.