Bronze Age
Bronze Age cultures differed in their development of the first writing. According to archaeological evidence, cultures in Mesopotamia (cuneiform script) and Egypt (hieroglyphs) developed the earliest viable writing systems.
The overall period is characterized by widespread use of bronze, though the place and time of the introduction and development of bronze technology were not universally synchronous. Human-made tin bronze technology requires set production techniques. Tin must be mined (mainly as the tin ore cassiterite) and smelted separately, then added to molten copper to make bronze alloy. The Bronze Age was a time of extensive use of metals and of developing trade networks (See "Tin sources and trade in ancient times"). A 2013 report suggests that the earliest tin-alloy bronze dates to the mid-5th millennium BC in a Vinča culture site in Pločnik (Serbia), although this culture is not conventionally considered part of the Bronze Age. The dating of the foil has been disputed.
Writing
Archaeologist Denise Schmandt-Besserat determined the link between previously uncategorized clay "tokens", the oldest of which have been found in the Zagros region of Iran, and the first known writing, Mesopotamian cuneiform. In approximately 8000 BC, the Mesopotamians began using clay tokens to count their agricultural and manufactured goods. Later they began placing these tokens inside large, hollow clay containers (bulla, or globular envelopes) which were then sealed. The quantity of tokens in each container came to be expressed by impressing, on the container's surface, one picture for each instance of the token inside. They next dispensed with the tokens, relying solely on symbols for the tokens, drawn on clay surfaces. To avoid making a picture for each instance of the same object (for example: 100 pictures of a hat to represent 100 hats), they 'counted' the objects by using various small marks. In this way the Sumerians added "a system for enumerating objects to their incipient system of symbols".