On the one level, events and individuals are placed in an absolute chronology: the exact years and sometimes even months and days of the events and biographies are known.
On the other level, the exact years may not be known, but it is known that one feature is earlier or later in relation to another; this is typically the case on an excavation, where the different archaeological strata allow objects found to be placed in a relative historical framework.
Methods fall into one of two categories: relative or absolute.
It is important to remember that this method give the age of the mineral, not the artifact.
So we can't pick up an artifact that's made from volcanic rock and get a potassium argon date on the artifact.
Paleontologists still commonly use biostratigraphy to date fossils, often in combination with paleomagnetism and tephrochronology.
A submethod within biostratigraphy is faunal association: Sometimes researchers can determine a rough age for a fossil based on established ages of other fauna from the same layer — especially microfauna, which evolve faster, creating shorter spans in the fossil record for each species.