The text examines the restorations made in the first half ot the twentieth century on the two main churches of Grado, the basilica of St. Eufemia and the church of St. Maria delle Grazie, where are until now conserved most of the mosaic floors built in the sixth century AD by Patriarch Elias.
The restorations were initially performed on the basis of indications of Alois Riegl and the Austrian Central Commission for monuments conservation while, after the First World War, the churches were radically restored by Italian Superintendency. In the first restoration can be noticed a strictly conservative approach that aims to a clear distinguishability between the additions and the original work, while the later profoundly altered the appearance of the buildings and also affected the mosaics, where the lacunae were integrated according to other principles.
