Pendent Silver Seals of Venetian Doges from the Collection of Nicolay Likhachev: a Technological Study

Abstract

The article examines the materials and constructional features of ten silver seals of the Doge of Venice originating from the collection of Academician Nikolai Petrovich Likhachev (1862—1936) and kept at the St. Petersburg Institute of History of the Russian Academy of Sciences. Addressing to this collection is justified and logical, since Nikolai Likhachev was the founder of sphragistics in Russia, and his collection played a special role in the formation of this auxiliary historical discipline. The silver seals stand out from the entire set of Western European seals due to their unusual construction, which has no analogues in Western European sigillography. They are made like hollow silver boxes, filled with a unknown substance. Optical microscopy in reflected light, X-ray fluorescence analysis and FTIR spectroscopy were used for technological analysis. X-ray fluorescence analysis (XRF) showed that the box was made of copper-silver alloy (Ag 94.5—83.55 %) in various percentages with minor admixtures of Zn, Pb, Fe, Ni, Au. Three seals contain Hg (up to 3 %). However, visual inspection did not confirm the version of amalgamation, as there are no characteristic rubbings. This question requires further investigation. FTIR spectroscopy of one of the specimens revealed that the specimen was not composed of resin, as the organoleptic analysis would suggest, but of beeswax, which had reacted with the metal, resulting in the formation of salts of free fatty acids contained in the wax. Finally, it was found that the design of three of the ten seals did not allow them to be securely attached to the document. Thus, these seals did not perform their main function — protection against forgery. This fact, combined with the more difficult technique compared to others, may explain the rarity of seals of this construction.