From earliest times, lightness, adaptability and flexibility have been the qualities associated with tent construction. Network, membrane, grid and space-frame structures belong to no specific architectural style or period. In a history that goes back many thousands of years, tent building has always expressed the potential for creating a simple shelter with a minimum of materials. Although tents meet the main criteria of a building, they have been largely neglected as a constructional form in the theory of architecture. It was not until the 19th century that architects first turned their attention to this form of structure, and then in a largely decorative way, although in 1861, Gottfried Semper described fabric forms of construction as one of the four basic elements of building. (Berthold Burkhardt)