the 14th century BC effectively crippled the Mitanni kingdom. After his invasion, Assyria succeeded in freeing itself from its suzerain, achieving independence once more under Ashur-uballit I ( 1363–1328 BC) whose rise to power, independence, and conquests of neighboring territory traditionally marks the rise of the Middle Assyrian Empire ( 1363–912 BC). Assyrian Empire Ashur-uballit I was the first native Assyrian ruler to claim the royal title šar ("king"). Shortly after achieving independence, he further claimed the dignity of a great king on the level of the Egyptian pharaohs and the Hittite kings. Assyria's rise was intertwined with the decline and fall of the Mitanni kingdom, its former suzerain, which allowed the early Middle Assyrian kings to expand and consolidate territories in northern Mesopotamia. Under the warrior-kings Adad-nirari I ( 1305–1274 BC), Shalmaneser I ( 1273–1244 BC) and Tukulti-Ninurta I ( 1243–1207 BC), Assyria began to realize its aspirations of becoming a significant regional power. These kings campaigned in all directions and incorporated a significant amount of territory into the growing Assyrian Empire. Under Shalmaneser I, the last remnants of the Mitanni kingdom were formally annexed into Assyria. The most successful of the Middle Assyrian kings was Tukulti-Ninurta I, who brought the Middle Assyrian Empire to its greatest extent. His most notable military achievements were his victory at the Battle of Nihriya 1237 BC, which marked the beginning of the end of Hittite influence in northern Mesopotamia, and his temporary conquest of Babylonia, which became an Assyrian vassal 1225–1216 BC. Tukulti-Ninurta was also the first Assyrian king to try to move the capital away from Assur, inaugurating the new city Kar-Tukulti-Ninurta as capital 1233 BC. The capital was returned to Assur after his death. Tukulti-Ninurta I's assassination 1207 BC was followed by inter-dynastic conflict and a significant drop in Assyrian power. Tukulti-Ninurta I's successors were unable to maintain Assyrian power and Assyria became increasingly restricted to just the Assyrian heartland, a period of decline broadly coinciding with the Late Bronze Age collapse. Though some kings in this period of decline, such as Ashur-dan I ( 1178–1133 BC), Ashur-resh-ishi I (1132–1115 BC) and Tiglath-Pileser I (1114–1076 BC) worked to reverse the decline and made significant conquests, their conquests were ephemeral and shaky, quickly lost again. From the time of Eriba-Adad II (1056–1054 BC) onward, Assyrian decline intensified. The Assyrian heartland remained safe since it was protected by its geographical remoteness. Since