The Sumerians of ancient Mesopotamia invented the first writing some 5,000 years ago. Having already established the first true civilisation by introducing agriculture and domesticizing cattle, they also decided it was more efficient to record their economic transactions in writing rather than use tokens to represent the number beasts and the amount of harvest they traded. Their initial use of simple pictograms, i.e. drawings which represented actual things, quickly developed into a complex system of symbols where items were illustrated by one sign and their volume by another.
As the symbols evolved, the notes that were recorded on clay tablets became more cuneiform or wedge shaped, owing to the wedge-tipped reed the Sumerians used as a writing implement. The shapes were initially drawn in vertical columns, but the writing later changed direction to that of the horizontal rows, reading the symbols from left to right. Rediscovered in the 1800s, cuneiform script was consequently found to be the first means of chronicling events in writing.
Challoner, Jack, (edit) '1001 Inventions That Changed the World', New Burlington Books, London, 2009, p.68.