Adad-nirari I (1307 BCE – 1275 BCE or 1295 BCE - 1263 BCE) was a king of Assyria. He is the earliest Assyrian king whose annals survive in any detail.
Adad-nirari I was a king of substantial military consequence in the development of the Assyrian kingdom. In his reign, Assyria began to play a large role in the history of Mesopotamia.
He conquered northern Mesopotamia and subdued the Mitanni empire. His surviving records indicate that he defeated King Nazimaruttash of Kassites, at the battle of Kar-Ishtar. He also defeated Mitanni kings Shattuara I and his son Wasashatta. This victory led his to incorporate all Mesopotamia under his rule. In wars against Hittites, he again lost large parts of Mesopotamia. In the east, he successfully defended his kingdom against the mountain tribes.
A bronze sword of Adad-nirari I can be seen in the Metropolitan Museum of Art.