Rome concurred the world with bronze swords. Iron still beat the heck out of bronze when it became generally available. If you need to harden copper, it may be alloyed w/ beryllium, which also makes the material "non-sparking". A very useful characteristic in some circumstances.
Regards,
GtG
FYI: The oldest bronze smeltering site in the world is in Thailand.
agreed - but isnt beryllium nasty stuff ?