Ribbed Glass Bowl, 1st century. This type of vessel represents a Roman manufacturing breakthrough that made high-quality glassware broadly affordable for the first time. The ribs were pressed into a heated glass disk with a tool, and then the disk was heated over a convex form. The resulting bowl shape was slowly cooled and then turned on a lathe to polish the rim and apply incised detail. Finally, the bowl was fire-polished in the furnace. It is in pristine condition.