Windows, light and a view are self-evident parts of contemporary interiors. This was not the case in Scandinavia during the Middle Ages (c. 1050-1520 CE), when closed spaces without wall openings were standard. Windows fulfilling modern needs and regulations, providing rooms with light and a view, did not come into common use until the 18th century, and in some contexts even later. The perception of light and darkness, and of what is understood to be light or dark, is changeable - as are people's sensorial experiences and their definitions of the senses. The provision of as much light as possible has not always been the most desirable quality in buildings, even in rooms provided with windows. The importance of and need for light have varied a lot over time and in different situations. During the Middle Ages, light openings were used in a more distinct and direct way, to meet specific requirements - not to provide rooms with an ambient level of light. Looking at the use of lighting equipment during the same period, it seems that both daylight and artificial light were used in similar, more specific and situational ways. When it comes to a view, this was not something that was expected in any room, or from any window, during the medieval period. An overall purpose with the thesis is to discuss how people have related to windows, light and lighting inside buildings during the Middle Ages, both in Sweden generally and in the two regional research areas of Gotland and Uppland in particular. One of the starting points is that the materiality of windows and the use of artificial light were closely bound up with people?s perceptions of and attitudes to light in indoor environments