Most likely, shortly after the first humanoid figured out how to pick up a stick and use it as a weapon. That is, likely sometime well before civilization began, when humans were still hunter-gatherers. And, possibly well before humans (as a species) existed - there is very strong evidence to suggest that several ape species engage in warfare, which would almost certainly mean that pre-humans did too.
So, maybe as much as several million B.C.E.
Adam and Eve's battle over the apple
the earliest or oldest known system of writing is Cuneiform.
The oldest known fossils are prokaryotic.
Tanzania is one of the oldest known counties
The oldest known vegetable is the pea.
In which hemispheres will you find the oldest known mummies: Northern or Southern?
the oldest known indian cultural periiod was the mississippian period
The oldest known dog is "Bobi", a 30-year-old farm dog from Portugal.
Jericho, the world's oldest known city, developed on the Jordan River.
The oldest form of writing known to man is Cuneiform used in Mesopatamia.
Lilith or Lilitu is technically the oldest vampyre in history
The turtle is the oldest known reptile.
The oldest soup known to man is Hippopotumus Soup.