I stumbled upon the following remark from Freeman Dyson:
The most important invention of the last two thousand years was hay. In the classical world of Greece and Rome and in all earlier times, there was no hay. Civilization could exist only in warm climates where horses could stay alive through the winter by grazing. Without grass in winter you could not have horses, and without horses you could not have urban civilization. Some time during the so-called dark ages, some unknown genius invented hay, forests were turned into meadows, hay was reaped and stored, and civilization moved north over the Alps. So hay gave birth to Vienna and Paris and London and Berlin, and later to Moscow and New York.
Is it really true, that hay was only invented in the Middle Ages in Europe? Is hay really such an important invention? What about other civilization like e.g. the Mongols who used a lot of horses. Didn’t they also have hay?