Dong Son
Solheim and others have shown evidence for a "Nusantao" maritime trading network ranging from Vietnam to the rest of the archipelago as early as 5000 BC to 1 AD. The Bronze Age Dong Son culture flourished in Northern Vietnam from about 1000 BC to 1 BC. Its influence spread to other parts Southeast Asia. The region entered the Iron Age era in 500 BC, when iron was forged also in northern Vietnam still under Dong Son, due to its frequent interactions with neighboring China.