The two unusual both in the form and subject bronze objects were acquired for the museums of Berlin in 1935 from the collection of Albert Figdor, one of the largest Viennese art collectors. Attributed earlier to the Padua sculptor Andrea Riccio, now they are considered the work of another master from Padua, Agostino Zoppo (1515-1572), who served as a foundry under Jacopo Sansovino, the chief sculptor of Venice in the 16th century. Each of them depicts the gates of the underground kingdom of Hades, inspired by Ovid's Metamorphosis, which described in detail the tortures of the inhabitants of Tartarus, seen by descending Juno. A considerable number of mythological characters (Sisyphus, Tantalus, Titius and others) inhabit a gloomy landscape, giving it a phantasmagoric character. In the inventory of Zoppo's workshop, compiled after his death, two pairs of similar sculptures are mentioned. Two more similar works are now in the collection of the Victoria and Albert Museum, London. The holes in their upper part give reason to assume that they could be used as censers.
The metal composition was determined. The surface was cleaned and consolidated.