Today marks the second installment in a series of articles by HumanProgress.org called Centers of Progress. Where does progress happen? The story of civilization is in many ways the story of the city. It is the city that has helped to create and define the modern world. This bi-weekly column will give a short overview of urban centers that were the sites of pivotal advances in culture, economics, politics, technology, etc. Part 1 can be found here.

Our second Center of Progress is Uruk, the world’s first large city and the birthplace of writing around 3200 BC. By creating the first writing system, the people of Uruk revolutionized humanity’s ability to exchange information.

Before the invention of writing, the only way people could communicate was by speaking to each other in person. Communication over vast distances and across long stretches of time was restricted by the fallibility of human memory. It was possible to send a messenger to a faraway city, but there was always a risk that the messenger would not recite the message accurately. People were able to pass down knowledge and histories through oral traditions from one generation to the next, but the details tended to change over time.

Today, Uruk is an uninhabited archeological site preserved in the desert of southern Iraq. It is part of a UNESCO World Heritage Site, honoring the “relict landscape of the Mesopotamian cities.” You can still see the remains of the city walls and gates, make out the shape of the streets and the layout of the houses from their crumbling foundations, and view the cracked steps of the temple mounds.

Today’s Uruk is quiet and ghostly. But if you were to visit Uruk in the late 4th millennium BC, you would have entered a thriving hub of art and commerce populated by around 10,000 inhabitants. That would increase to between 30,000 and 50,000 inhabitants by the beginning of the 3rd millennium BC.

For perspective, Uruk’s population in the late 4th millennium BC was about the same as the population of the small town of Brattleboro, Vermont, today. But Uruk was among the first settlements to achieve a population of that size and is considered by many to be the world’s first large city. In the year 3200 BC, Uruk was the largest city in Mesopotamia and possibly in the entire world.

As Uruk’s population grew, its society became more complex and the Sumerian civilization (the world’s first true civilization, which flourished in southern Mesopotamia between 4500 BC and 1500 BC) reached its creative peak. Surviving tablets indicate that Uruk had over a hundred different professions, including ambassadors, priests, stonecutters, gardeners, weavers, smiths, cooks, jewelers and potters.

Walking through the streets of Bronze Age Uruk, you would have seen merchants hawking their wares, beautiful gardens with palm trees, and temples rising high above all of the other structures. The temple complexes were places of religious importance, but that was not their only purpose. You may have seen men carrying clay pitchers filled with grain into the temples, because these imposing monuments were also where the people of Uruk stored their surplus food.

The arid desert around Uruk had few natural resources. To compensate for that lack, the people developed robust trade networks with other communities. They imported wood from the Taurus, Zagros and Lebanon mountain ranges, and lapis lazuli stones from as far away as Afghanistan. Some of these valuable imports were also stored in the temples.

Near one of the temple’s entryways, you may have witnessed a history-altering breakthrough. You may have seen an accountant or record-keeper marking a clay tablet each time a pitcher of grain entered the temple. He would have made a small picture of a grain stalk next to his tally marks, like the city’s record-keepers had done for centuries.

But if you looked more closely, you would have observed that his picture was not really a picture at all. That is because, over the course of many years, the record-keepers’ pictures had become simpler to make taking inventory of goods faster. Eventually, the image that was used to represent grain in the temple records no longer even vaguely resembled a grain stalk. The pictographs evolved, in other words, to become non-pictorial symbols that represented concepts⁠—such as grain.

By agreeing on a set of abstract symbols to represent common goods stored in their temple warehouses, Uruk’s accountants were able to avoid the laborious chore of making detailed drawings on their clay tablets.

Eventually, the people of Uruk used these written symbols to not only represent different concepts, like grain or fish or sheep, but to also represent the spoken sounds that people used to express those concepts. Once they had symbols for different sounds, it became possible to write out names or other words phonetically. After that innovation, the Sumerians were able to write down more than simple inventory lists. They could also create increasingly complex documents. Their written output ranged from lengthy epic poems and wisdom literature, to genealogies and lists of kings.

According to the writings of the ancient Sumerians, the city of Uruk was built by the mythical king Enmerkar. This epic hero was thought to have been the son of the Sumerian sun god Utu and a cow (an animal that the Sumerians revered and associated, due to its production of milk, with motherhood). Enmerkar is said to have ruled Uruk for hundreds of years. If the mythical figure of Enmerkar is loosely based on a real ruler, then he would have lived at the end of the 4th or beginning of the 3rd millennium BC.

In Sumerian legend, which was preserved in the epic Enmerkar and the Lord of Aratta, it is Enmerker who is credited with the invention of writing. The legend says that he did so during a period of tense negotiation with a neighboring king, the ruler of the rival city-state Aratta. Enmerkar was purportedly dissatisfied that his messenger, who was exhausted from traveling back and forth between Uruk and Aratta reciting messages, could only relay messages of limited length to convey to the neighboring king.

So Enmerkar purportedly picked up some clay, magically created a complete written language, and proceeded to write a message down for his messenger to deliver to the king of Aratta. Specifically, the myth states:

[King Enmerkar’s] speech was substantial, and its contents extensive. The messenger, whose mouth was heavy, was not able to repeat it. Because the messenger, whose mouth was tired, was not able to repeat it, the lord of [Uruk] patted some clay and wrote the message as if on a tablet. Formerly, the writing of messages on clay was not established. Now, under that sun and on that day, it was indeed so.

That colorful legend shows that the Sumerians valued written language so highly that they thought only a king (and an ostensible demigod, no less) could create something so important.

In reality, writing was not invented by a king, but by the city’s accountants. Moreover, it was not created all at once in a burst of creative genius, but arose gradually over many generations. It was not originally created to gain an advantage in international diplomacy, but instead came about for the far less glamorous reason mentioned earlier: book-keeping. As such, the earliest writings that survive to today tend to be inventory lists, shopping lists, wage records, lists allocating rations for temple workers, and shopping receipts.

The people of Uruk wrote with reeds and clay, because those materials were both widely available. Uruk is situated amid the Mesopotamian Marshes, a rare watery landscape in the middle of an otherwise dry desert. The wetlands, fed by the Euphrates and Tigris rivers, may have been larger in the past than they are today. A channel of the Euphrates that has since dried up is thought to have flowed very close to Uruk.

After cutting a reed from the marshy banks of the Euphrates, the people of Uruk at some point discovered that when a single reed is pressed, with its cut edge facing down, into soft wet clay, it produces a distinctive wedge shape. When the clay dried and hardened, that shape was preserved.

When the accountants simplified their pictographs into ever more abstract symbols, those symbols took the form of certain arrangements of wedge-shaped marks, which then became the first characters or “letters.” That is why the earliest writing system is now known as cuneiform, from the Latin for “wedge-shaped.”

Originally, record-keepers would take inventory by writing up-to-down on their clay tablets, as if making a list. After many years of writing that way, the scribes developed an innovative new system of writing from left-to-right. That innovation reduced the risk of smudging what had been written before the clay dried.

However, the temple priests and other literate people of Uruk were accustomed to reading records from top-to-bottom, not from left-to-right, and did not care for the scribes’ new system. The scribes came up with a solution that would allow themselves to write from left-to-right, while still allowing their tablets to be read from top-to-bottom. Ingeniously, the scribes simply wrote down versions of their written symbols that were rotated by ninety degrees. Writing their symbols sideways allowed those reading the tablets in the old way, from top-to-bottom, not to be inconvenienced.

Eventually, people began to read the symbolic script in the same way that it was written, from left-to-right. But because the already abstract symbols were rotated, they became even more abstract, hastening the process of moving from simple pictographs to cuneiform characters. Below, see the evolution of the cuneiform character meaning “head,” from a simple picture drawn around the year 3000 BC into a highly abstract cuneiform character almost a thousand years later.

Today, Uruk is best-known as the city of the ancient hero Gilgamesh, as described in the Epic of Gilgamesh. That epic poem began as a series of poems composed around 2100 BC, although the most complete surviving version is considerably more recent, dating to the 12th century BC.

Scholars believe that a real person named Gilgamesh probably ruled Uruk sometime between 2800 and 2500 BC, and came to be described as a demigod and larger-than-life hero after his death. Thanks to the invention of writing, people today are able to enjoy not only Sumerian literature, but all of human literary output ranging from the plays of William Shakespeare to the science fiction of Isaac Asimov.

For being the world’s first large city and the birthplace of writing, Bronze Age Uruk deserves to be recognized as our second Center of Progress. Writing gave humanity a new means of creative self-expression and the ability to exchange information across generations and across the globe.