Stained Glasses are the coloured glass used for making decorative windows and other objects through which light passes. Strictly speaking, all coloured glass is “stained,” or coloured by the addition of various metallic oxides while it is in a molten state; nevertheless, the term stained glass has come to refer primarily to the glass employed in making ornamental or pictorial windows. The singular colour harmonies of the stained-glass window are due less to any special glass-colouring technique itself, however, than to the exploitation of certain properties of transmitted light and the light-adaptive behaviour of human vision.
Stained Glass has been practiced since the 12th century or even before that. It was a tedious method to color the glass by adding metallic salts during its manufacturing. The palaces and mansions of kings and princes were decorated with stained glass.