CTS FOCUS 07 - PLM in Action at the Mosque

In: Focus

If we traveled along the legendary Silk Road and, upon reaching Samarkand, ventured into the rugged mountainous region to the south, after about one hundred kilometers southwest, we would arrive at Langar Ota and could visit the Sufi mosque, dating from the 15th–16th centuries.

It is one of the few rural Sufi mosques in Uzbekistan that have remained largely intact since the 15th century, during the Timurid dynasty, and is renowned for its exquisite cut-tile mosaic decoration, preserved for approximately 600 years.

The mosque, visited monthly by around a thousand pilgrims, contained significant Islamic religious artifacts, including the cloak of the Prophet Muhammad.

In 2022, the Chicago Center for Cultural Heritage Preservation at ISAC received authorization from the Uzbekistan Cultural Heritage Agency to initiate a conservation program for the Langar Ota mosque.

The project is funded by a grant from the Ambassadors Fund for Cultural Preservation of the U.S. Department of State, managed through the U.S. Embassy in Tashkent. Activities concluded at the end of 2024.

A key priority of the project was the stabilization of the mosaic panels, which were extensively detached and deformed, located on the sides of the mihrab (the niche within a mosque indicating the direction of Mecca) of the main prayer hall, and at risk of collapse.

These panels consist of cut ceramic tiles arranged in mosaics (koshinborush in Uzbek), representing a distinctive art form characteristic of Silk Road cities such as Bukhara and Samarkand. The incredible variety of geometric patterns, letters forming Qur’anic suras, and floral decorations are in some areas enhanced with gold leaf.

Since Uzbekistan lacks local suppliers of conservation materials, part of the preparation for the November 2024 mission involved researching and sourcing fluid mortars suitable for filling voids and consolidating detached areas of the mosaic panels.

After evaluating the most reliable options available, the PLM mortar line was selected, offering formulations tailored for various applications. Specifically, the following were chosen:

PLM-SM: selected for its high mechanical properties, designed for re-adhering mosaic supports. It was extensively used to restore adhesion between the panels and masonry and to begin filling voids between the tesserae and the backing mortar.

PLM-AL: chosen for its lightness, it was applied after the initial consolidation with PLM-SM, to complete the filling of voids in more bulging areas, reducing the load on the most fragile sections.

The selection of these materials aimed to ensure effective and long-lasting interventions while minimizing additional stress on the mosaic structures.

Our thanks go to the Italian restorers involved in the project, Fabio Colombo and Elisa Pannunzio, whose valuable contributions provided the foundation for this article. Additional information is available on the ISAC website: https://isac.uchicago.edu/sites/default/files/uploads/shared/docs/Publications/Annual-Reports/2023-2024/AR2023-24_Cultural_Heritage_Preservation.pdf