History and development of windmills
The earliest reference to a windmill describes how Abu hu’lu’a, a Persian “builder of windmills”, was captured after he had assassinated the Caliph in A.D. 644. Windmills in Seistan, on the borders of Iran and Afghanistan, were mentioned by al-Mas’udi in his encyclopaedia published in A. D. 947 These were horizontal mills, in which the sails rotated horizontally on a vertical shaft, and such mills have persisted until today in that part of the world. It is thought that the earliest vertical windmills in Western Europe may have been invented by Crusaders returning from Persia, where they saw the horizontal type.
European post-mills and cylindrical tower-mills (Jan de Strada - late sixteenth century).
Towards the end of the eighteenth century, John Hill a famous Grahamstown miller, built a horizontal windmill with two pairs of stones in Grahamstown. It is probable that the horizontal windmill was an adaptation of the horizontal “Greek” water-mill, and that the familiar windmill with vertically rotating sails (like Mostert’s Mill) was derived from the Vitruvian water-mill. The vertical type appears to have been invented in north-west Europe where the first reference to a windmill is of one in Normandy when in A.D. 1180 there is a record of a piece of land near a windmill being granted to the Abbey of St. Sauvere de Vicomte. The dated records tend to support the theory that the idea of a windmill was first introduced by returning Crusaders