C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago, although special preparation methods occasionally make accurate analysis of older samples possible.

When was carbon dating founded?

1946 Professor Willard Libby, a chemist at the University of Chicago, first proposed the idea of radiocarbon dating in 1946. Three years later, Libby proved his hypothesis correct when he accurately dated a series of objects with already-known ages.