The history of the world or human history is the history of humanity from the earliest times to the present, in all places on Earth, beginning with the Paleolithic Era. World history encompasses the study of written records, from ancient times forward, plus additional knowledge gained from other sources, such as archaeology. Ancient recorded history begins with the invention of writing. However, the roots of civilization reach back to the period before writing—humanity's prehistoryin the Paleolithic Era, or "Early Stone Age". Later, during the Neolithic Era, or New Stone Age, came the Agricultural Revolution (between 8000 and 5000 BCE) in the Fertile Crescent, where humans first began the systematic husbandry of plants and animals. Agriculture spread until most humans lived as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed these communities to expand into increasingly larger units in parallel with the evolution of ever more efficient means of transport.