Comment by tonytran2015: Iron swords, strategic advanced weapons have appeared 2800-3000 years ago but were still largely unknown outside Northern Europe. In 200BC Han China still banned the sale of cast-iron plow tips to NamYue (Nam-Viet in Vietnamese) for strategic reason.
Part of a Bronze Age settlement was uncovered at Must Farm quarry, at Whittlesey, near Peterborough, in Cambridgeshire, England. The site has been described as “Britain’s Pompeii” due to its relatively good condition, including the “best-preserved Bronze Age dwellings ever found” there, which all appear to have been abandoned suddenly following a catastrophic fire. Research now suggests that the site was less than one year old at the time of destruction.
…Archaeologists found two roundhouses, from about 1000–800 BCE, …
Iron and Bronze Age swords from Must Farm
For comparison: Famous Goujian sword, Hubei Provincial Museum, 500 BCE (https://en.m.wikipedia.org/wiki/Sword_of_Goujian)