If we knew the precise length of reign for every Egyptian king, chronology would be no problem.However, we do not even know the number of kings for all periods, and there is also the possibility that reigns overlapped by coregency or in times of political disunity.For their own religious and administrative purposes, the Egyptians compiled lists of kings, sometimes with the exact length of reign.
The main surviving kinglists from ancient Egypt beside the 'Palermo Stone' are hieroglyphic inscriptions of Thutmose III (Karnak, probably a list of statues displaced in temple construction), Sety I and Ramses II (both at Abydos), and a fragmentary hieratic manuscript from Thebes (Turin Canon).
Kinglists in Greek, apparently compiled by a third century BC Egyptian priest named Manetho, are preserved in summaries by early Christian writers, with excerpts in other writers of the Roman Period and later, notably the Jewish historian Josephus.
Artefacts often have a distinctive style or design, which developed over a period of time.
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.
For a long period in the 20th century Egyptian and Near Eastern chronology seemed to be the earliest of absolute chronologies, and imports from these areas were used to reconstruct the chronology of European prehistory.
With the introduction of objective quantifiable methods such as dendrochronology and Carbon-14 dating, over the past half century, European and North American archaeology have developed independent and more reliable chronologies, that often make it possible to date more precisely than in Egypt. For Egypt absolute year dates can only be established back to the beginning of the Late Period, from links to Greek chronology, and then from Assyrian king-lists and other Near Eastern sources, back to the Ramesside Period (still debated). The Egyptians dated by the year of reign of the king on the throne (for example 'year 3 of king X').
The dating of remains is essential in archaeology, in order to place finds in correct relation to one another, and to understand what was present in the experience of any human being at a given time and place.
Inscribed objects sometimes bear an explicit date, or preserve the name of a dated individual. However, only a small number of objects are datable by inscriptions, and there are many specific problems with Egyptian chronology, so that even inscribed objects are rarely datable in absolute terms.