What's the History of the Window in Castles?

We don't often spend a lot of time thinking about the window itself. Is there a point at which we cano of mark the first use of the window? When does a window become a window, rather than just an opening in the wall? Yes and ars. In terms of the british window, it's hard to say really. It depends on how you define a window. And i was really impressed by the windows that we saw in the great hall at chepstow. Although the glass itself has gone being told how people would sit in the window seats there.