<Li> in its earliest form from Old Persian birinj, biranj (برنج) "brass" (modern berenj), piring (پرنگ) "copper", from which also came Serbo - Croatian pìrinač "brass", Georgian brinǰao "bronze", Armenian płinj "copper". </Li> <P> The discovery of bronze enabled people to create metal objects which were harder and more durable than previously possible . Bronze tools, weapons, armor, and building materials such as decorative tiles were harder and more durable than their stone and copper ("Chalcolithic") predecessors . Initially, bronze was made out of copper and arsenic, forming arsenic bronze, or from naturally or artificially mixed ores of copper and arsenic, with the earliest artifacts so far known coming from the Iranian plateau in the 5th millennium BCE . It was only later that tin was used, becoming the major non-copper ingredient of bronze in the late 3rd millennium BC . </P> <P> Tin bronze was superior to arsenic bronze in that the alloying process could be more easily controlled, and the resulting alloy was stronger and easier to cast . Also, unlike arsenic, metallic tin and fumes from tin refining are not toxic . The earliest tin - alloy bronze dates to 4500 BCE in a Vinča culture site in Pločnik (Serbia). Other early examples date to the late 4th millennium BC in Egypt, Susa (Iran) and some ancient sites in China, Luristan (Iran) and Mesopotamia (Iraq). </P> <P> Ores of copper and the far rarer tin are not often found together (exceptions include one ancient site in Thailand and one in Iran), so serious bronze work has always involved trade . Tin sources and trade in ancient times had a major influence on the development of cultures . In Europe, a major source of tin was the British deposits of ore in Cornwall, which were traded as far as Phoenicia in the Eastern Mediterranean . </P>

What was the importance of the introduction of bronze and iron