Tumi is Peru's national symbol at present time, but was largely used by sun worshipping cultures such as Inca and pre-Inca cultures that flourished in ancient Peru.
With a distinctive semi-circular blade, they were made of gold-alloy, bronze, cooper or silver-alloy. During Inca times for instance, it was used by the High priest to sacrifice a llama in the Inty Raymi celebration.
Incas considered themselves to be descendants of the sun god - Apu Inti - and every year on the 24th of June they would celebrate Inti Raymi to thank Apu Inti for the abundant crops - potato, maize, etc- or ask for a better one the next season. Inti Raymi is still annually held at Cuzco, Peru, being one of the biggest popular celebrations in South America, second only to the most famous carnival in Brazil, held at Rio de Janeiro.
Until recently, they were only studied by archaeologists through looted pieces recovered from grave robbers, but never in context, scientifically studied.
In 2006, a major discovery changed that, when a burial site of the pre-Inca nobility of Sican was found in Ferrañafe, not far from Chimbote, some 700 km to the North of Lima.
Several tumis were unearthed then, made in an alloy of cooper, silver and gold.
The Sican developed a sophisticated metalworking techniques and are believed to be descendants of the Moche or Mochica culture...remember Sipan?
Sican flourished in Northern Peru between AD 750-1375 and reached their peak between 900 and 1100 AD, around 100 years before the Incas rose to prominence.