The image to the right shows two pages from the second section.
By comparing the parallel columns, the reader can determine which events were contemporaneous, or how many years separated two different events.
Chronology is the science of locating historical events in time.
It relies upon chronometry, which is also known as timekeeping, and historiography, which examines the writing of history and the use of historical methods.
Dendrochronology is used in turn as a calibration reference for radiocarbon dating curves.
The familiar terms calendar and era (within the meaning of a coherent system of numbered calendar years) concern two complementary fundamental concepts of chronology.
An epoch is the date (year usually) when an era begins. It was used to identify the Roman year by a few Roman historians.
Much of modern historical datings and chronology of the ancient world ultimately derives from these two works.
The fundamental problem of chronology is to synchronize events.
By synchronizing an event it becomes possible to relate it to the current time and to compare the event to other events.
Radiocarbon dating estimates the age of formerly living things by measuring the proportion of carbon-14 isotope in their carbon content.
Dendrochronology estimates the age of trees by correlation of the various growth rings in their wood to known year-by-year reference sequences in the region to reflect year-to-year climatic variation.