clerestory

clerestory - noun - an outside wall of a room or building that rises above an adjoining roof and contains windows

Probably one of the more important pieces of architecture, thinking primarily of ancient churches, palaces, or other large governemnt buildings is the clerestory (the clear story). This is how a building of vast dimensions was light. Candles just couldn't handle the load. Imagine being in Notre Dame or the Malmesbury Abbey and trying to read your sermon notes, or, if you happened to be lucky enough to be in the orchestra, your music. Buildings without windows are dark buildings indeed and it takes a lot of candles to even raise the light level enough to be tolerable to ambulate sans tripping. Windows and daylight are a much better solution. Then the problem is: how to get light in without blinding the people. The answer: put the windows way up high so the light comes down to the floor of the building without distracting people with a nice view to the outdoors and not having the sunlight full in their eyes as they peer toward the altar.