Daylight is one of the essential elements in the human experience of architectural space, and this is especially the case with the historic buildings that predate the wide-spread use of electric light. With a historic building, the architect’s original design intent for daylighting may be diminished by a variety of factors: environmental context, replacement of glazing material, soiling, window treatments, introduction of artificial light, interventions for the improvement of energy efficiency, and removal or abandonment of external shading devices such as shutters. By operating computational simulation of the indoor daylight environment on a chosen historic building, the Pennsylvania Academy of the Fine Arts, this thesis is to estimate how light quality has altered over time and how it has changed the viewer’s appreciation of a space.