Various artifacts which are believed to date from the Bronze Age (approximately 3300 BCE to 1200 BCE) are made of iron. Historians have disputed whether the Bronze Age population had the know-how and technical means to smelt iron ore.

An alternative theory suggests that they might have made the iron objects by melting meteorites - which typically have a high iron content.

A 2017 report in the Journal of Archaeological Science describes analysis of the iron/cobalt/nickel content of some of the objects.

Bronze Age iron artifacts could be derived from either meteoritic (extraterrestrial) or smelted (terrestrial) iron. This unresolved question is the subject of a controversy: are some, all or none made of smelted iron?"

The report concludes :

The present results complementing high quality analyzes from the literature suggest that (most or) all irons from the Bronze Age are derived from meteoritic iron, until some transition period, which occurred supposedly close to about 1200 BC. The next step will be to determine where and when terrestrial iron smelting appeared for the first time."

Source : Journal of Archaeological Science, Volume 88, December 2017, Pages 47-53 (a full copy of which may be found here )