Nobody is exactly sure when Bristol Blue Glass was first made but we do know that the dazzling combination of the fine cobalt oxide with the recently invented lead crystal gave the most remarkable deep, rich blue, the like of which had never been seen before. It was Isaac Jacobs who first began to mass-produce, at incredibly high prices, Bristol Blue Glass. His father, Lazarus had started their Nonsuch Flint Glass Works in the 1780s. By the turn of the century the company held a royal warrant and were making glass for the aristocracy of Europe. Isaac was the first glassmaker in history to sign his work offering an undisputed provenance. In 1851, Bristols glassmakers were invited to show their skills to the world at the Great Exhibition opened by Victoria and Albert. They made Ruby Glass for the very first time, using 24 carat gold to give the glass its delicious ruby tones. https://www.bristol-glass.co.uk/history.html