Beyond the analysis laid out by A Senefelder, with which I have to say that I agree, if I had to bet anything on this, my money would go to the tapestries series "The conquest of Tunis".
In 1535, when campaigning against the pirate kingdom of Tunis, held by Barbarossa and the Turks, Charles V took with him the Dutch artist Jan Cornelisz Vermeyen. From his experiences in the successful campaign he produced a series of detailed sketches that were afterwards used as a model for weaving (in the 1550's, I think) the monumental tapestries that constituted a chronicle of the event. The sketches (14, I think, of which 12 survived until today) can be seen today on display on the walls of the Kunsthistorisches Museum, in Vienna, where they fill a whole wing (they are huge). Many of the actual tapestries are also preserved nowadays in various Royal Spanish Collections.
The style of the images depicted in the chalice is quite familiar, and remembers me strongly of these series. The fact that I recently had to privilege of going to Vienna, appreciate them first-hand and becoming enthralled by their beauty and detail, may be conditioning my perception, though
These tapestries were already well-known and well-admired in their time and have been since then, so it wouldn't be strange to find figures extracted from them in other pieces of decorative art.
