cases the Assyrians followed the principle of primogeniture, wherein the oldest son inherits. More evidence in favor of Ashur-nadin-shumi being the crown prince is Sennacherib's construction of a palace for him at the city of Assur, something Sennacherib would also do for the later crown prince Esarhaddon. As an Assyrian king of Babylon, Ashur-nadin-shumi's position was politically important and highly delicate and would have granted him valuable experience as the intended heir to the entire Neo-Assyrian Empire. In the years that followed, Babylonia stayed relatively quiet, with no chronicles recording any significant activity. In the meantime, Sennacherib campaigned elsewhere. His fifth campaign in 699 BC involved a series of raids against the villages around the foot of Mount Judi, located to the northeast of Nineveh. Sennacherib's generals led other small campaigns without the king present, including a 698 BC expedition against Kirua, an Assyrian governor revolting in Cilicia, and a 695 BC campaign against the city of Tegarama. In 694 BC, Sennacherib invaded Elam, with the explicit goal of the campaign being to root out Marduk-apla-iddina and the other Chaldean refugees. The Elamite campaign and revenge In preparation for his attack on Elam, Sennacherib assembled two great fleets on the Euphrates and the Tigris. The latter fleet was then used to transport the Assyrian army to the city of Opis, where the ships were then pulled ashore and transported overland to a canal that linked to the Euphrates. The two fleets then combined into one and continued down to the Persian Gulf. At the head of the Persian Gulf, a storm flooded the Assyrian camp and the Assyrian soldiers had to take refuge on their ships. They then sailed across the Persian Gulf, a journey which Sennacherib's inscriptions indicate was difficult since repeated sacrifices were made to Ea, the god of the deep. Successfully landing on the Elamite coast, the Assyrians then hunted and attacked the Chaldean refugees, something that both Babylonian and Assyrian sources hold went well for the Assyrians. Sennacherib's account of the campaign describe the affair as a "great victory" and list several cities taken and sacked by the Assyrian army. Although Sennacherib at last got his revenge on Marduk-apla-iddina, his arch-enemy had not lived to see it, having died of natural causes before the Assyrians landed in Elam. The war then took an unexpected turn as the king of Elam, Hallutash-Inshushinak I, took advantage of the