This red glass tankard was probably made in southern Germany in around 1700. Historically, it was extremely difficult to produce a clear, deep red colour in glass and the subject of how the technique was perfected is discussed by Reino Liefkes (see below):
'In 1679 the alchemist and glass-maker Johann Kunckel (1630-1703), working for the Elector of Brandenburg near Potsdam, published his celebrated treatise on glass-making, Ars vitraria experimentalis....' Part of this dealt with the manufacture of a ruby-coloured glass, the colour of which was derived from a precipitate of gold. Undoubtedly other glass-makers had preceded him in the manufacture of this tint, but he appears to have been the first to achieve consistant results in sizeable batches. The use of gold to colour glass may seem strange today, but it should be remembered that both gold and ruby were believed to be empowered with magical properties - the latter bringing strength and health, and safeguarding its owner against sorcery....Kunckel was secretive about the exact processes involved in making ruby glass. Nevertheless, by the end of the century the secret of its manufacture had spread to other parts of the Holy Roman Empire; and during the late 17th and early 18th centuries glass with a deep ruby tint was produced in Dresden and Bohemia, and in Munich and Freising in southern Germany.'

This piece, of relatively simple shape, it thought to have been made in Freising. The gilded mount engraved with baroque scrolls is typical of the Dresden and Augsburg metal workers and was probably applied soon after the tankard was made.

Reino Liefkes (ed). Glass, V. & A. Publications, 1997, reprinted 2000.