From carbon dating

Radiocarbon is then taken in by plants through photosynthesis, and these plants in turn are consumed by all the organisms on the planet.So every living thing has a certain amount of radiocarbon within them.

Looking at the graph, 100% of radiocarbon in a sample will be reduced to 50% after 5730 years.

In 11,460 years, half of the 50% will remain, or 25%, and so on.

The Greeks consider the first Olympic Games as the beginning or 776 BC.

The Muslims count the Prophet’s departure from Mecca, or the Hegira, as their beginning at AD 662.

After an organism dies, the radiocarbon decreases through a regular pattern of decay. The time taken for half of the atoms of a radioactive isotope to decay in Carbon-14’s case is about 5730 years.