Q. When and why warm kiln fusing glass was developed?

Warm glass techniques were believed to have been used as early as the second millennium B.C. by the ancient Mesopotamians, deriving from existing ceramics and metalworking techniques. Ancient Egyptians continued the use of glass casting and fusing techniques. These techniques were used as well by the Greeks and Romans up until around the 2nd or 3rd century AD. When glassblowing came into widespread use, warm glass methods of glassworking lost popularity(Walker 1-2) until around the 19th century when they began to be used again by Europeans, particularly with the pate de verre movement.

Keith Cummings attributes this resurgence of interest in warm glass techniques in the 19th century to several factors: 1) advent of the Industrial Revolution, which forced/allowed craft workers to get out of the business of producing everyday objects when processes were mechanized in factories. Craft workers then moved towards the Fine Arts mode of creating and began to experiment with processes and effects. 2) Impact of other cultures on Europeans, for instance, the popularity of Egyptian imagery and design which influenced Frederick Carder and Henry Cros both.

According to Lucartha Kohler, "fused glass is one of the oldest forming methods....the glassmakers of the Roman Empire made wonderful blowls by fusing together tiny pieces of fancy rod known as millifiore (thousand flowers.) Even earlier, the Egyptians made tiny tiles and amulets by fusing together small chips of glass."

Sources:

Cummings, Keigh. A History of Glassforming. Philadelphia: U of Pennsylvania P, 2002.

Cummings, Keith. Techniques of Kiln-Formed Glass. Philadelphia: U of Pennsylvania P, 1997.

Kohler, Lucartha. Glass: An Artist's Medium. Iola, WI: Krase Publications, 1998.

Walker, Brad. Contemporary Warm Glass. Clemmons, NC: Four Corners International, 200, 2002.

Please let me know if you have further questions!