Ishme-Dagan From Wikipedia, the free encyclopedia. Ishme-Dagan was the son of the Amorite king Shamshi-Adad I, put on throne of Ekallatum by his father after a successful military attack. He ruled the area of the upper Tigris, including the city-state of Assur. After Shamshi-Adad's death he managed to rule for a few years before being ousted from power by local forces. His brother, Yasmah-Adad, ruled at the same time in the city of Mari, where the correspondence between the father and two sons was found by archaeologists.