T he world's oldest known system of writing was influenced by symbols used for trade — engravings found on cylinders used in the exchange of farming produce and textiles, a new study suggests.

The researchers looked at cylinder seals that date to 4400 to 3400 B.C.E., with an emphasis on those used before the development of writing. When they compared symbols on the cylinder seals with ...

Some of the seals examined in the new study date to about 4400 B.C. — more than 1,000 years before the development of writing. "We focused on seal imagery that originated before the invention of ...