Sin () or Suen (, ) also known as Nanna ( ) was the Mesopotamian god representing the moon. While these two names originate in two different languages, respectively Akkadian and Sumerian, they were already used interchangeably to refer to one deity in the Early Dynastic period. They were sometimes combined into the double name Nanna-Suen. A third well attested name is Dilimbabbar (). Additionally, the moon god could be represented by logograms reflecting his lunar character, such as d30 (), referring to days in the lunar month or dU4.SAKAR (), derived from a term referring to the crescent. In addition to his astral role, Sin was also closely associated with cattle herding. Furthermore, there is some evidence that he could serve as a judge of the dead in the underworld. A distinct tradition in which he was regarded either as a god of equal status as the usual heads of the Mesopotamian pantheon, Enlil and Anu, or as a king of the gods in his own right, is also attested, though it only had limited recognition. In Mesopotamian art, his symbol was the crescent. When depicted anthropomorphically, he typically either wore headwear decorated with it or held a staff topped with it, though on kudurru the crescent alone served as a representation of him. He was also associated with boats.
The goddess Ningal was regarded as Sin's wife. Their best attested children are Inanna (Ishtar) and Utu (Shamash), though other deities, for example Ningublaga or Numushda, could be regarded as members of their family too. Sin was also believed to have an attendant deity (sukkal), Alammuš, and various courtiers, such as Nineigara, Ninurima and Nimintabba. He was also associated with other lunar gods, such as Hurrian Kušuḫ or Ugaritic Yarikh.
The main cult center of Sin was Ur. He was already associated with this city in the Early Dynastic period, and was recognized as its tutelary deity and divine ruler. His temple located there was known under the ceremonial name Ekišnugal, and through its history it was rebuilt by multiple Mesopotamian rulers. Ur was also the residence of the en priestesses of Nanna, the most famous of whom was Enheduanna. Furthermore, from the Old Babylonian period onward he was also closely associated with Harran. The importance of this city as his cult center grew in the first millennium BCE, as reflected in Neo-Hittite, Neo-Assyrian and Neo-Babylonian sources. Sin's temple survived in later periods as well, under Achaemenid, Seleucid and Roman rule. Sin was also worshiped in many other cities in Mesopotamia. Temples dedicated to him existed for example in Tutub, which early on was considered another of his major cult centers, as well as in Urum, Babylon, Uruk, Nippur and Assur. The extent to which beliefs pertaining to him influenced the Sabians, a religious community who lived in Harran after the Muslim conquest of the Levant, is disputed.
Names
While it is agreed that the two primary names of the Mesopotamian moon god, Nanna and Sin (Suen), originated in two different languages, respectively Sumerian and Akkadian, it is not possible to differentiate between them as designations of separate deities, as they effectively fully merged at an early date. points out this phenomenon is already attested in sources from Lagash from the Early Dynastic period, where the name Nanna does not appear, and Sin is the form used in both Sumerian and Akkadian context. The process of conflation presumably started prior to the invention of cuneiform. Sometimes the double name Nanna-Suen was used, as evidenced for example by a short theological text from the Ur III period listing the main deities of the official pantheon. It is sometimes used to refer to this god in modern Assyriological publications too.
Nanna
The precise etymology of the name Nanna is unknown, though it is agreed that it is not a genitive construction. It is first attested in the Uruk period. In earliest cuneiform texts from Uruk and Ur it was written as (d)LAK-32.NA, with NA possibly serving as a phonetic complement. The name of the city of Ur (Urim) was accordingly written as LAK-32.UNUGki (), "residence of Nanna", per analogy with toponyms such as Zabalam, INANNA.UNUGki. In later periods LAK-32 coalesced with ŠEŠ (the ideogram for "brother"), and Nanna's name came to be written as dŠEŠ+KI or dŠEŠ.KI, though phonetic spellings such as na-an-na are attested too, for example as glosses in lexical lists.