The Stone Age began 2 to 3 million years ago and ended at around 3300 B.C. The dates for the beginning and end of the Stone Age are ranges because the definition of the age refers to the tools which were developed at different times around the world. The Stone Age can be further divided into periods, although there are several different systems in place for this division. One common type of division is into three periods: the Paleolithic, Mesolithic and Neolithic Periods. Other systems of division separate the Stone Age into the early, middle and later Stone Age. The times for each of these systems also varies based on location as the periods are defined by technological development rather than dates.