Prehistory (100,000 - 3,400 BC)
Modern humans (and at one time Neanderthals) inhabited Iran for more than 100,000 years before the first written records. Over the millennia, Iran became populated through a series of migrations that remain little understood. Paleolithic cultures were nomadic and subsistence-based, probably tied to seasonal movements across the landscape following herds of animals. Archaeological surveys and excavations have revealed bone and stone tools, human remains, and other anthropogenic material in caves and open-air encampments.
The Neolithic period (ca. 8,500-4,500 BC) was defined primarily by the shift from hunting and gathering to agriculture and animal husbandry. Permanent settlements were founded with growing populations. Archaeologists categorize Neolithic sites into two horizons based on the presence of ceramics or pottery, which provides a valuable diagnostic tool to assess settlement patterns. Initially, during the "aceramic phase," villages were not generally inhabited year-round. By the “ceramic period," people had largely settled into sedentary life and crafted tools, storage containers, and other implements from an expanding range of resources.
The prehistoric era is punctuated by a relatively brief age called the Chalcolithic (ca. 4,500 - 3,400 BC), or Copper Age, during which communities in ancient Iran began developing an understanding of metalworking. On a broader scale, societies grew in number and population, initiating trends like craft specialization and social stratification. The resulting technological and societal innovations of this age brought greater efficiency to many aspects of life in Ancient Iran and opened the door to even more dramatic changes.