Stained glass went into decline during the Renaissance, when the techniques we now call “Gothic” came to be seen as naive if not barbarous. It wasn’t until the 19th Century that artists began to look afresh at the medium. William Morris, an innovative designer and a radical socialist, executed not only religious scenes but secular commissions like King Arthur and Sir Lancelot for the Gothic Revival buildings of the day. (William Morris/King Arthur and Sir Lancelot/Wikipedia)