It is referred to as the cushion clay
tablet and it is believed to have been

made around 2600 BC. This tablet
shows the details of the transaction

of grains. The upper part means
135,000 liters.

This is the item in question: barley.
They drew it as it is.

The left side represents the terms
of the transaction. It says 37 months.

This tablet is a record that somebody
lent or borrowed 135,000 liters of

barley for a period of 37 months. 
What, then, do these symbols mean?

According to research, the sound represented
by these symbols is coushem.

Unlike the other symbols found on 
these ancient relics, the meaning

of these are a mystery.

The two signs in these early tablets,
coushem, are puzzling because

they don't mean anything.

Um, these two signs individually
each have a meaning but together

they don't seem to mean anything.

And so, it's been suggested quite
plausibly that this is somebody's name.

That somebody wrote these two signs
because the name sounded the same way.

A coom sign meaning something, and a shim sign
meaning something else but together

just somebody's name.

The phonetic symbols coo and shim
came together to form cooshim,

a symbol that represents a sound. 
This marked the beginning of salavak writing.

It was the birth of rebus writing system.
A single example of rebus can be found

using a car and a cat. This representation,

however, does not mean a car and a cat.
The sounds of the words represented

by these pictographs, car and pet, could
be used to mean something completely

different. In this case, carpet. 
These symbols, meaningless by

themselves, come together to form a word.
This type of writing system is known a rebus,

a representation of words in the form
of pictures or symbols.

In the modern era this concept 
is seen as quite simple and basic

but for people in ancient times the 
adoption of a rebus writing system

was a truly revolutionary development.

With the adoption of more complex rebuses,
the number of cuneiforms ranged from

about 1500 to about 600. The previously 
complicated pictures became simpler.

More advanced forms of cuneiform
were found in relics north of Moor.

The most famous among them were 
from the poor.