It was probably a younger brother of Shalmaneser who ascended the throne of Assyria in 721. Assuming the old name of Sharru-kin (Sargon in the Bible), meaning “Legitimate King,” he assured himself of the support of the priesthood and the merchant class by restoring privileges they had lost, particularly the tax exemptions of the great temples. The change of sovereign in Assyria triggered another crisis in Babylonia. An Aramaean prince from the south, Marduk-apal-iddina II (the biblical Merodach-Baladan), seized power in Babylon in 721 and was able to retain it until 710 with the help of Humbanigash I of Elam. A first attempt by Sargon to recover Babylonia miscarried when Elam defeated him in 721. During the same year the protracted siege of Samaria was brought to a close. The Samarian upper class was deported, and Israel became an Assyrian province. Samaria was repopulated with Syrians and Babylonians. Judah remained independent by paying tribute. In 720 Sargon squelched a rebellion in Syria that had been supported by Egypt. Then he defeated both Hanunu of Gaza and an Egyptian army near the Egyptian border. In 717 and 716 he campaigned in northern Syria, making the hitherto independent state of Carchemish one of his provinces. He also went to Cilicia in an effort to prevent further encroachments of the Phrygians under King Midas (Assyrian: Mitā).

In order to protect his ally, the state of Mannai, in Azerbaijan, Sargon embarked on a campaign in Iran in 719 and incorporated parts of Media as provinces of his empire; however, in 716 another war became necessary. At the same time, he was busy preparing a major attack against Urartu. Under the leadership of the crown prince Sennacherib, armies of agents infiltrated Urartu, which was also threatened from the north by the Cimmerians. Many of their messages and reports have been preserved. The longest inscription ever composed by the Assyrians about a year’s enterprise (430 very long lines) is dedicated to this Urartu campaign of 714. Phrased in the style of a first report to the god Ashur, it is interspersed with stirring descriptions of natural scenery. The strong points of Urartu must have been well fortified. Sargon tried to avoid them by going through the province of Mannai and attacking the Median principalities on the eastern side of Lake Urmia. In the meantime, hoping to surprise the Assyrian troops, Rusa of Urartu had closed the narrow pass lying between Lake Urmia and Sahand Mount. Sargon, anticipating this, led a small band of cavalry in a surprise charge that developed into a great victory for the Assyrians. Rusa fled and died. The Assyrians pushed forward, destroying all the cities, fortifications, and even irrigation works of Urartu. They did not conquer Tushpa (the capital) but took possession of the mountain city of Muṣaṣir. The spoils were immense. The following years saw only small campaigns in Media and eastern Anatolia and against Ashdod, in Palestine. King Midas of Phrygia and some cities on Cyprus were quite ready to pay tribute.

Sargon was now free to settle accounts with Marduk-apal-iddina of Babylonia. Abandoned by his ally Shutruk-Nahhunte II of Elam, Marduk-apal-iddina found it best to flee, first to his native land on the Persian Gulf and later to Elam. Because the Aramaean prince had made himself very unpopular with his subjects, Sargon was hailed as the liberator of Babylonia. He complied with the wishes of the priesthood and at the same time put down the Aramaean nobility. He was satisfied with the modest title of governor of Babylonia.

At first Sargon resided in Kalakh, but he then decided to found an entirely new capital north of Nineveh. He called the city Dur-Sharrukin—“Sargonsburg” (modern Khorsabad, Iraq). He erected his palace on a high terrace in the northeastern part of the city. The temples of the main gods, smaller in size, were built within the palatial rectangle, which was surrounded by a special wall. This arrangement enabled Sargon to supervise the priests better than had been possible in the old, large temple complexes. One consequence of this design was that the figure of the king pushed the gods somewhat into the background, thereby gaining in importance. Desiring that his palace match the vastness of his empire, Sargon planned it in monumental dimensions. Stone reliefs of two winged bulls with human heads flanked the entrance (see photograph); they were much larger than anything comparable built before. The walls were decorated with long rows of bas-reliefs showing scenes of war and festive processions. A comparison with a well-executed stela of the Babylonian king Marduk-apal-iddina shows that the fine arts of Assyria had far surpassed those of Babylonia. Sargon never completed his capital, though from 713 to 705 bc tens of thousands of labourers and hundreds of artisans worked on the great city. Yet, with the exception of some magnificent buildings for public officials, only a few durable edifices were completed in the residential section. In 705, in a campaign in northwestern Iran, Sargon was ambushed and killed. His corpse remained unburied, to be devoured by birds of prey. Sargon’s son Sennacherib, who had quarreled with his father, was inclined to believe with the priests that his death was a punishment from the neglected gods of the ancient capitals.