Glassmaking originated around 2500 B.C. in Mesopotamia, and by the mid-first millennium B.C. it had spread throughout the ancient world. The number of vessels made from glass remained limited, however, until the introduction of two important technical advances—the use of the blowpipe and closed multipart molds—in the late first century B.C. and the early first century A.D., respectively. These advances revolutionized the glass industry under the Roman Empire, making glass vessels accessible to all and allowing producers to create a wide range of shapes, sizes, and usages. Some of the earliest vessels made by mold blowing bear the names of the craftsmen who “signed” the molds.

In the early first century A.D. the most outstanding examples of Roman mold-blown glass were made by a craftsman called Ennion, and products of his workshop are the focus of the exhibition "Ennion: Master of Roman Glass," at The Metropolitan Museum of Art. This is the first exhibition of ancient glass organized by the Metropolitan, which has one of the finest collections of this material in the world.