Rybczynski 23: "The Middle Ages not only produced illuminated books, but also eyeglasses, not only the cathedral, but also the coal mine. Revolutionary changes occurred in both primary industry and manufacturing. The first recorded instance of mass production--of horseshoes--occurred during the Middle Ages. Between the tenth and the thirteenth century, a technological boom produced the mechancial clock, the suction pump, the horizontal loom, the waterwheel, the windmill, and even, on both shores of the English Channel, the tidal mill. Agricultural innovations formed the economic foundation for all this technical activity. The deep plow and the idea of crop rotation increased productivity as much as fourfold, so that agricultural yields in the thirteenth century would not be surpassed for another five hundred years. Far from being a technological Black Hole [sic], the Middle Ages marked the authentic beginning of industrialization in Europe."