The sudden appearance of the sash-window on the architectural scene towards the end of the seventeenth century and the speed with which this most ingenious product of seventeenth-century building technology spread over half of the Western world in the course of the next century, have always surprised the modern observer. Yet, despite much speculation, neither the sash-window’s inventor nor the date and place of its first appearance are known.
Among the many theories that have emerged in the one and a quarter centuries since the origin of the sash-window became a subject of serious discussion in letters to the editor of Notes and Queries, several have so little foundation in fact that they can be summarily dismissed. Other theories, although equally devoid of a sound factual base, at least rise to the level of informed conjecture and as such deserve further consideration.