A period in the history of the Assyrian empire extending from the 14th-12th centuries BC. In the Late Bronze Age, Assyria was dominated by the Mitanni state, but in the 14th century BC, Assyria became dominant. Ashur-uballit I created the first Assyrian empire and initiated the Middle Assyrian period. With the help of the Hittites, he destroyed the dominion of the Aryan Mitanni (a non-Semitic people from upper Iran and Syria) and ravaged Nineveh. Later, allied with the Kassite successors in Babylonia, Ashur-uballit ended Hittite and Hurrian rule. By intermarriage he then influenced the Kassite dynasty and eventually dominated all of Babylonia, thus paving the way for the Neo-Assyrian mastery during the Sargonid dynasty (12th to 7th century). The succeeding Assyrian kings expanded the empire through northern Mesopotamia and the mountains to the north and briefly occupied Babylonia. Several kings weakened Assyria, but then others brought back its dominion. Middle Assyrian is also the name of a form of cuneiform that was used extensively in writing law code and other documents. Middle Assyrian laws were found on clay tablets at Ashur (at the time of Tiglath-pileser I, 1114-1076 BC).