At the moment of death the C14 begins to decay at a rate that scientists already know from other experiments.
Archaeological scientists have two primary ways of telling the age of artefacts and the sites from which they came: relative dating and absolute dating.It's just a bit frustrating when you can't get an absolute conclusion, and many differing opinions. I have a gold ring which I believe is ancient but also important! The way it's constructed, the way the internal sides of the rings gold are melted with faults that look like bits of silver And the slightly differing colours, the hand carved gem and its,inscription! Landslides and slips can completely change the topography of an entire archaeology site burying what was once on top by that which is much older, hence reversing the strata layers.A more precise and accurate archaeology dating system is known as absolute dating and can in most circumstances provide a calendar year to the object.