Today, Eridu is often considered to be one of the oldest permanent settlements in Mesopotamia, and perhaps even in the world. The ancient Sumerians also believed that Eridu was the first city in the world and they documented that belief in the Sumerian King List and the Eridu Genesis . At least 18 layers of settlement are found at the site, could the ancient Sumerian belief be possible?
Archaeological evidence shows that the earliest structures date to the 6th millennium BC. The city reached its zenith during the 4th millennium BC and continued to be inhabited until around the 7th century BC. By then, however, the city had lost its importance.

Some of the baked bricks used in the construction of the Sumerian ziggurat at Eridu, southwest of Nasiriyah, Iraq, are

stamped with the name of King Ur-Nammu (2123-2106 BC). (David Stanley/ CC BY 2.0 )

A Tell of 18 Levels
Eridu (known today as Tell Abu Shahrain) is located about 20 km (12.5 miles) to the southwest of the famous city of Ur. As its modern name indicates, the archaeological site is a tell, which is a huge mound formed over the millennia as a result of new settlements being built over the ruins of the previous ones. The tell rises to a height to 7 meters (23 feet), and is formed by 18 levels of occupation, according to the archaeological excavations. The bulk of this has been dated to the Ubaid and Uruk periods, which lasted from the 6th to 4th millennia BC.

The ancient Sumerians themselves made mention of Eridu’s antiquity. In the Sumerian King List , for example, it is written that “After the kingship descended from heaven, the k ingship was in Eridug.” In addition, in the creation myth known as the Eridu Genesis , it is said to have been one of the five cities that existed before the Deluge, the others being Bad-Tibira, Larak, Sippar, and Suruppak.
The God of Eridu Temple

The patron god of Eridu was Enki (known also in Akkadian as Ea), the god of water. According to Sumerian mythology, the settlement was founded by Enki, and it was from this city that civilization was spread to other parts of the land. Although Enki was initially a local god, he rose in importance as the city grew in influence, resulting in him being incorporated into the pantheon of other cities as well. In Eridu, Enki’s temple is known as E-Abzu (Abzu may be translated as ‘Deep Ocean’, and refers to the underground spring from which all life is believed to have begun).

                 
 Rough map of the Eridu mound showing the main ziggurat, temple, and a few buildings. (Cush/CC BY SA 3.0)

Archaeological excavations of the E-Abzu have revealed that the temple began as a small room containing what has been referred to by scholars as a ‘cult niche’ and an ‘offering table’. Over the millennia, however, the inhabitants built new temples over the ruins of the old ones, each bigger than the last. The E-Abzu eventually became a large ziggurat, an apt reflection of Enki’s status as a major deity. It has been proposed that the E-Abzu may have been the largest of the ancient Mesopotamian ziggurats.
Economic Activities
Although the E-Abzu is the focal point of the site’s archaeology, there are either elements of interest. More recent excavations, for instance, have revealed that during the Ubaid period, the city was a pottery production center. This is evident in the pottery production center. This is evident in the pottery works, which had large scatterings of pottery fragments and kiln waste. Additionally, remains of fishing nets, weights, and even models of reed boats have been found at the site, suggesting that fishing was a major economic activity carried out by the inhabitants.