500 B.c.

[conon394]

I was referring to the comment about iron being used to increase agricultural output spurring this growth of civilization. In order for this to happen the increase would need to be significant. In order for it to happen in the first place the need would be necessary as well. If an iron shod plow wasn't much better vs. existing technology then there wouldn’t be much of an increase. Tree and fruit crops aren't nearly as productive as cereal crops.

I was commenting on your suggestion that there was some kind of resistance to the heavy plough. I don’t see any resistance, the Greeks simply did not need a heavy plough, and the Romans adopted and developed one as soon as they started operating in Northern Europe. Did the Romans produce de-novo a fully operational medieval plough circa AD 1200, obviously not; but they did adopt heavy ploughs in places where they were needed and refined them substantially by the 4th century AD.

You might also consider that while iron as applied to plows might not lead to greater crop productivity, iron tools might well have reduced the amount of labor needed for other farming tasks (tree felling etc).

Slave driven economies discouraged the use of animal, wind, steam, or water power because they used slaves. A slave economy retards innovation because you don't need to improve technology to increase production; you just need, more slaves. It also causes people to consider manual labor a task for "lesser" people (look at the US South or colonial Spain as examples). The full potential of the heavy plow was realized after the Roman era once animal's hoofs were properly protected and after the development of the horse collar.

I don’t think you can demonstrate that in that proposition in the classical world. Water power (mills) and water lifting (screws, pumps, etc) appear in the Hellenistic Greek World in the 3rd century BC. All of theses technologies subsequently diffused widely throughout the Roman Empire. Water mills and water powered ore crushers are a typical feature of the very large Imperial era mines that also use large scale slave labor.
Horse shoes and collars are a somewhat irrelevant, since the Romans used oxen to pull their heavy plows in Northern Europe, not horses. The horse collar is certainly a very useful invention if you want to use horses for ploughs, but it is not the only harness that can be used. The Romans world showed a rather steady development of harness types and certainly had harnesses that were as effective as the breast-strap. Overall I say Hellenistic and Roman world showed quite a bit of technical advancement glass-blowing, the crane, chain gearing, ratcheted gears, differential gearing, significant development in things like sail types, harbor construction, etc.

Looking down on manual laborers, crafts, and tradesmen (by Aristocrats and the landed gentry) hardly stopped with the end of classical slavery. The great bulk of much of the ancient literary evidence was written by and for the ‘Good and the Beautiful’ as the Greeks would say, not the Hoi-polloi. The evidence from votive offering, and tombstones hardly suggest the working classes of the ancient world though of themselves has doing deeming work, just because slaves also often did the same work.