[quote=Partisan]I see. Did the europeans not have better weapons armor and tools etc than Asians?[/quote]

No, Europe was barely populated in 4000 BC; Mesopotamia (Cradle West) saw the creation of pocket-sized empires with armies just big enough to ruin another city's day, but these were the best of the best. We're talking EARLY Bronze Age here. Europe's civilizations were still stuck in the Neolithic - Stonehenge, by comparison, was completed 900 years after our starting point! Asia was about on par with metalworking with Mesopotamia, but their bronzework was typically non-military. Regardless of whether or not they had bronze WEAPONS in Asia, they had the capability of making them.