Spiral threads or cables of molten glass added to vessels are the most common decorative technique in Roman-period glass. Threads can be hairlike in thinness, or stout. The video shows threads of both types. In Jerusalem, sometime about 40 B.C., it was discovered that molten glass could be inflated. To make this phenomenon useful and practical, manufacturing processes had to be invented. This occurred during a rapid expansion of the Roman Empire that eventually included the entire Mediterranean Basin and extended to the far eastern coast: present-day Israel. Through an extensive trade of goods and the widespread movement of people and know-how, glassblowing found its way to the Italian peninsula. It took root and developed quickly. Glassblowing spread to become—then, as now—the predominant method of making glass vessels. Learn more at https://romanglassblowing.cmog.org/. The resource is a follow-up to Gudenrath's popular Techniques of Renaissance Venetian Glassworking (https://renvenetian.cmog.org/) and Technique of Renaissance Venetian-Style Glassworking (https://renvenetianstyle.cmog.org/)