Neither in Hammurabi’s letters, nor upon the stele inscribed with his code of laws, is any reference made to the contemporary governor or ruler of Assyria, but on a contract tablet preserved in the Pennsylvania Museum a name has been recovered which will probably be identified with that of the ruler of Assyria in Hammurabi’s reign. In legal and commercial documents of the period of the First Dynasty of Babylon the contracting parties frequently swore by the names of two gods (usually Shamash and Marduk) and also that of the reigning king. Now it has been found by Dr. Banke that on this document in the Pennsylvania Museum the contracting parties swear by the name of Hammurabi and also by that of Shamshi-Adad. As only gods and kings are mentioned in the oath formulas of this period, it follows that Shamshi-Adad was a king, or at any rate a patesi or ishshakku. Now from its form the name Shamshi-Adad must be that of an Assyrian, not that of a Babylonian, and, since he is associated in the oath formula with Hammurabi, it is legitimate to conclude that he governed Assyria in the time of Hammurabi as a dependency of Babylon. An early Assyrian ishshakku of this name, who was the son of Ishme-Dagan, is mentioned by Tiglath-Pileser I, but he cannot be identified with the ruler of the time of Hammurabi, since, according to Tiglath-Pileser, he ruled too late, about 1800 B.C. A brick-inscription of another Shamshi-Adad, however, the son of Igur-kapkapu, is preserved in the British Museum, and it is probable that we may identify him with Hammurabi’s Assyrian viceroy. Erishum and his son Ikunum, whose inscriptions are also preserved in the British Museum, should certainly be assigned to an early period of Assyrian history.