The creation of a reliable Chronology of Ancient Egypt is a task fraught with problems. While the overwhelming majority of Egyptologists agree on the outline and many of the details of a common chronology, disagreements either individually or in groups have resulted in a variety of dates offered for rulers and events. This variation begins with only a few years in the Late Period, gradually growing to a decade at the beginning of the New Kingdom, and eventually to as much as a century by the start of the Old Kingdom. The reader is advised to include this factor of uncertainty with any date offered either in Wikipedia or any history of Ancient Egypt.