The earliest known pocketknives date to at least the early Iron Age. Many folding knives from the Viking era have been found. They carried some friction binders, but more often they seem to have used folding knives that used a closure to keep the blade open.
Answer: The first knives were invented by homo sapiens during prehistoric times and were used as weapons, tools and eating utensils. The Oldowon was used up to 2.5 million years ago and is the oldest known knife-like tool to be discovered as of 2014.