The following is copyrighted material from an upcoming book on Scagliola, and cannot be reproduced without the expressed written consent of the author, James Gloria.
Certainly there were finishes imitative of marble since antiquity using paints and plasters. However, the unique mixture of highly-polished, marbled plaster that I use is generally attributed to 17th century Italian monks, Guido Fassi being the most prominent. Fassi and others produced incredibly detailed inlaid panels for altar fronts and tables. While these intricately inlaid surfaces may have begun in imitation of Pietra Dure, Scagliolists quickly took advantage of the infinite variety of color, plasticity and patterns possible with plaster. The ease with which it is carved enables incredible renderings of fine lace, delicate flowers and the interwoven tendrils of grottesca designs . By the early 17th c., the panels of Fassi, Enrico Hugford and others practically exploded with Rococo arabesques, trompe l’oeil maps and finely-crosshatched renderings of saints.An alternate theory is that the technique may have begun in Switzerland or Germany. Either way, it eventually spread to the rest of continental Europe, eventually making its way to England by way of the architects Robert & James Adam. By then, the technique was adapted for more monumental architectural purposes: sheathing columns, walls and even floors, most notably in Syon House, designed by Robert Adam. These broader marbling techniques are usually called “stucco marmo”, (marbled stucco) to distinguish them from the more intimately scaled, inlaid scagliola panels. The British also introduced a new material, Keene’s Cement, to meet the demands of scale and institutional wear. Much harder than regular plaster of Paris, it could be polished to a high sheen and would better resist the scuffs and scratches of public architecture.In making its way to the new world, the technique acquired another approach under the moniker, “marezzo”.