The church of Hagia Sophia in Thessaloniki was deserted after its destruction by fire in 1890. Almost two decades later the Ottoman administration, decided to undertake a full-time reconstruction of the monument. This great enterprise was carried out between the years 1907-1911 and was supervised by the celebrated byzantinologist Charles Diehl. A note written and addressed to the Academie des Inscriptions on January 17 1908 by M. Le Tourneau, who started the relevant work on the mosaic decoration of the church in 1907, supplies information on the course of the works in Hagia Sophia, undertaken by the French.