The Roman writer on agriculture Columella, who died around AD 70, gives a detailed description of the manufacture of hay (Latin: faenum) in his de re rustica 2.18, which reads as follows in the Loeb translation:
"It is best, moreover, that hay be cut before it begins to wither, as a greater quantity of it is harvested and it affords a more agreeable food for cattle. But a middle course should be followed in the curing, that it be gathered neither when very dry nor, on the other hand, while still green — in the one case because it is no better than straw if it has lost all its sap, and in the other because, if it has kept too much of it, it rots in the loft and often, when it becomes heated, it breeds fire and starts a blaze. Sometimes, too, when we have cut our hay a rain surprises us; and if the hay is soaked through it is useless to move it while wet, but better to let the upper side of it dry out in the sun. 2
2 Only then shall we turn it, and, when it is dry on both sides, we shall bring it together in windrows and then bind it up in bundles. And above all we shall lose no time in putting it under cover; or, if it is not convenient for the hay to be carried to the farmstead or tied into bundles, it will be well at any rate that all of it that had been dried out to the proper extent be built up into cocks and that these be topped off with very sharp peaks.
3 For by this method hay is very conveniently protected from rains; and even if there is no rain, it is still not amiss to build the aforesaid cocks, so that any moisture remaining in the hay may sweat and dry out in the piles. For this reason wise husbandmen, even in the case of hay brought under cover, do not store it away until they have allowed it to heat and cool for a few days in a loose pile. But now after the haymaking comes attention to the grain harvest; and that we may properly gather it, we must first put in readiness the implements with which the crops are harvested."
So much for the claim that "in the classical world of Greece and Rome and in all earlier times, there was no hay".