Modern Glass Buildings the Gothic period also, stained glasses were first used in the religious buildings only. As religious places were highly visited, stained glasses easily came into notice of the people and made them curious about this beautiful art form. Initially the religious stained glass windows were small in size thus, providing ample amount of light along with the beauty.
Hence, the churches of the medieval period are rightly said to be the patrons of the stained glass windows. So, we can safely say that the window treatments are being used since Gothic period. In this era the conventional designs were converted to more complex iconography.