Scene is too dark

Hey, I don’t know if this belongs here, but anyways:
I am building a throne room with a long corrigor. It has a lot of stained windows but somehow I cannot seem to make it brighter. The directional light doesn’t fall directly through because it is set in the same angle as the hallway.I placed rectangle lights in front of every window but it makes it only a tiny bit brighter. Point lights where Candles shall later be make only a small change. ANybody an idea?