The Byzantine church of Our Lady of the Castle is located in the Medieval City of Rhodes and was most likely built in the 11th century. Initially, it was the Orthodox metropolitan cathedral but, following the occupation of Rhodes by the Ioannite Knights, it was established as the archiepiscopal cathedral of the Latins which was dedicated to the Theotokos, bearing the name Sancta Maria Castelli Rodi. Following the damage it suffered during the earthquake of 1303, the Byzantine temple was turned into a three-nave basilica with a raised central nave and a tripartite sanctuary, covered by gothic groin vaults.

The restoration work began in July 2011, when the project was included in the NSRF - Operational Programme for Crete and the Aegean Islands, and was completed in 2014. A team from the Institute of Materials Science of NCSR Demokritos undertook the analysis of the existing mortar and submitted a proposal for both the replacement mortar as well as the best solution concerning the composition of the grouting provided for by the static study. This was followed by cleaning, via mechanical means, of all internal masonry surfaces and identification of the areas where the existing mortar existed but was unsound. Joint work was carried out, with the proposed replacement mortars, to all internal surfaces, and tubes were inserted, for the grout provided for, into the four internal square columns. The same procedure was followed in the North, East and South side and, at the same time, new wood windows were inserted. Particular attention was paid to maintenance of the frescoes which are built into the cathedral, as well as maintenance of the space’s excavation finds.

Over the previous decade, the monument was open to the public, hosting special cultural events and permanent exhibitions of Byzantine painting, as well as events related to the monument’s history.