when did humans start keeping track of years
History of calendars A number of prehistoric structures have been proposed as having had the purpose of timekeeping (typically keeping track of the course of the solar year). This includes many megalithic structures, and reconstructed arrangements going back far into the Neolithic period.
Neolithic The Neolithic (/ˌniːəˈlɪθɪk/ ( listen)[1]) was a period in the development of human technology, beginning about 15,200 BC, according to the ASPRO chronology, in some parts of the Middle East, and later in other parts of the world[2] and ending between 4500 and 2000 BC.