Radiocarbon dating service
This implies that it takes 5730 years for half of the 14C atoms in the organic matter to get decayed.
When an organism is dead the intake of the carbon-14 stops and in a 5730 year time period, half of the amount of carbon-14 present in the organic matter would have undergone beta decay to form stable Nitrogen-14.
Otherwise archaeologists had to resort t to the method of relative dating where by comparing with stratigraphically close objects [objects which are buried at the same depth will be approximately of the same era.] clue regarding the time period and historical styles were assumed or rather guesstimated. gsu.edu/hbase/nuclear/cardat.html>15 April 2009.
Prior to the development of radiocarbon dating it was difficult to determine the age of the artifacts unless it was accompanied with some chronologically specific things like a coin.
Carbon-14 has a half-life of 5,730 ± 40 years— during the succeeding 5,730 years.