“Preparatory drawing in red clay on stuccoed bricks. The design was to serve as a guide in the realization of the apse mosaic of the basilica of Sant’ Apollinare in Classe.
The original project involved the depiction of peacocks and doves in front of baskets of fruit and plant elements, to symbolize the tree of life. In the final mosaic, probably commissioned by Bishop Maximian, the birds and fruits were replaced by the two flocks of lambs on either side of the first Bishop Apollinare.
To prepare the drafting of a mosaic, in addition to the sinopia, other guide drawings were made on the subsequent layers of mortar.
The mortar was spread in portions that could be done in a single day of work, to prevent it from drying before placing all the tesserae. The last layer of mortar on which the tesserae were placed was coloured by diluting the earth in water: the chromatic traces served both as a reference for the colours to be used and to bring the mortar still visible in the interstices between the tesserae to tone.
The sinopia was found behind the mosaic during the restoration and consolidation works carried out between 1970 and 1973.
The part of the masonry removed from the church was placed on an aluminum profile structure coated with epoxy resin and glass wool, reproducing the original shape of the apse vault.”