Hammurabi's allies in northern Mesopotamia had sent their armies to the south to help Babylon. This caused unrest in the northern area. Hammurabi therefore returned north, stopping the unrest, and defeating Eshnunna. He then attacked and conquered the remaining cities in northern Mesopotamia, including Babylon's former ally Mari. It is possible that Mari surrendered to Babylon without any fighting happening. After this, Hammurabi was in control of most of Mesopotamia. Only Aleppo and Qatna, two western cities in modern Syria remained independent. When Hammurabi died in c. 1750 BC, his son became king.