Over millennia this technology became increasingly sophisticated, and was ultimately reflected in a pair of remarkable works, written in Arabic by Muslim scientists: The Book of Ingenious Devices, written in Baghdad in the middle of the 9th century, and The Book of Knowledge of Ingenious Mechanical Devices, written in Anatolia in the early 13th century.
These books, while often showcasing tricks, mechanical illusions and elaborate vanity pieces, represent some of humankind’s first attempts at valves, fail-safe systems, automatic controls, and other mechanisms central to engineering (for example, the camshaft, crankshaft, and escapement mechanism).
Dates and almonds, sugar and rice, were introduced to trade networks and became available in Europe’s less hospitable climates, where their popularity exploded, prompting more planting and more irrigation.
Almonds and almond milk filled Northern Europe’s cookbooks, a craze that we’d all recognize today, and it is hard not to imagine this rage for almonds causing medieval Spain the same sort of difficulties that California faces right now. Rainfall and, importantly, the number of days without any rain, are very similar in the almond-growing parts of California and Spain (and in the present-day Fertile Crescent: central Syria).
Oddly, irrigation records suggest that droughts were considerably more prevalent in the 14th century than in the centuries before and after. Farmers of less popular crops no doubt complained, peasants dessicated and nobles wrung their hands, worried that it would be dry forever, that they had planted for themselves a sort of apocalypse. All for that thirsty almond. But irrigation improved, the almond craze faded, and Spain did not dry up and blow into the sea.
