The natural beginning

From the earliest caves, daylight informed the lives of the inhabitants, initially in the difference between night and day; but as dwellings became more sophisticated, by means of openings or windows letting in light.

The history of architecture is synonymous with the history of the window and of daylighting from the initial crude openings, letting in light and air, heat and cold, the window was the vehicle for the introduction of daylight, and ultimately to the wondrous interiors of the mediaeval cathedral, the Baroque churches or the many private buildings of the eighteenth century.

The window has developed over the centuries, but its purpose of letting in daylight has remained its primary role; window openings required a suitable infill to modify the external climate. At first various materials were used, such as thin slabs of marble, sheets of mica or oiled paper, but it was not until the development of glass for windows that substantial progress could really be made.

Glass had been discovered as early as 3000 BC in Egypt, and was used for decorative objects, but it is known that small panes of hand-blown glass set into bronze frames were used for the infill to window openings during the Roman period. These were little different to the leaded lights of the mediaeval period, being limited to the small pane sizes governed by the manufacturing process.

It was left until the seventeenth century for large panes of glass to be developed in England and for larger windows to be made possible.

The history of windows is really the history of architecture, from the crude openings in the sides of early domestic buildings open to the atmosphere, or openings in the roof construction, allowing the entry of rain collected in a central pool.

The appearance of buildings of all periods reflects the nature of the windows, in some cases such as the mediaeval period, the shape and location of the windows being functionally related to the role played by daylighting, whilst in the Renaissance period the location and form of windows became more formalized, often being less well related to the interior spaces they served the elevation, the appearance of the building seen from the outside, became of prime importance, a consideration which lingers on today.

Windows have always led to innovation, and this can be seen in the stained glass windows of the great mediaeval cathedrals, telling the Christian story, where whole walls of glass were made possible by structures such as the flying buttress.

Windows had to serve military needs in fortified buildings, leading to slit windows from which arrows could be fired; with splayed sides having the desirable effect of reducing the contrast between the brightness of the window and the interior wall surface, a device which has continuing validity.

A further innovative means of daylighting was that developed for the lighting of the Baroque churches of southern Germany, where ‘indirect’ daylight onto the ornate decorations and ornaments of the church is gained from windows concealed from the direct view of the congregation. Indirect daylighting is equally valid today, as used by Basil Spence at Coventry Cathedral, or by Jorn Utson at the Bagsvaerd Church in Denmark.

Whilst the vertical windows set into the outside walls of buildings were clearly of the first importance, and continue to be so today, it was the roof lights allowing daylight into the central parts of buildings that had an important influence on the plan form of the stately homes of the seventeenth and eighteenth centuries. These took several forms, from domes such as that at Keddleston Hall (1759) where light enters from the top or Chiswick House (1725) where the dome is surrounded by windows in the sides, in both cases the method of daylighting allowed architects to have more flexibility to plan the central areas of their buildings. It is of interest that this method of introducing daylight to the centre of buildings has a resonance with the atria which we see in many buildings today (Figure 1.1 The Cathedral of Christ the Light, USA ).

5 Read the text again and answer the questions that follow (1-6):