The term māt Aššur is first attested as being used in the reign of Ashur-uballit I ( c. From the time of its rise as a territorial state in the 14th century BC and onwards, Assyria was referred to in official documentation as māt Aššur ("land of Ashur"), marking the shift to being a regional polity. In the Old Assyrian period, when Assyria was merely a city-state centered around the city of Assur, the state was typically referred to as ālu Aššur ("city of Ashur"). Ancient Assyria also left a legacy of great cultural significance, particularly through the Neo-Assyrian Empire making a prominent impression in later Assyrian, Greco-Roman and Hebrew literary and religious tradition. Innovations in warfare and administration pioneered in ancient Assyria were used under later empires and states for millennia thereafter. The success of ancient Assyria did not derive solely from its energetic warrior-kings, but also from its ability to efficiently incorporate and govern conquered lands through sophisticated administrative systems. The ancient Mesopotamian religion persisted at Assur until its final sack in the 3rd century AD, and at certain other holdouts for centuries thereafter.
The remaining Assyrian people, who have survived in northern Mesopotamia to modern times, were gradually Christianized from the 1st century AD onwards. Assyria experienced a recovery under the Seleucid and Parthian empires, though declined again under the Sasanian Empire, which sacked numerous cities in the region, including Assur itself. Though the core territory of Assyria was extensively devastated in the Medo-Babylonian conquest of the Assyrian Empire and the succeeding Neo-Babylonian Empire invested little resources in rebuilding it, ancient Assyrian culture and traditions continued to survive for centuries throughout the post-imperial period. The Assyrian Empire fell in the late 7th century BC, conquered by Babylonians, who had lived under Assyrian rule for about a century, and the Medes. Assyria was at its strongest in the Neo-Assyrian period, when the Assyrian army was the strongest military power in the world and the Assyrians ruled the largest empire then yet assembled in world history, spanning from parts of modern-day Iran in the east to Egypt in the west. In the Middle and Neo-Assyrian periods Assyria was one of the two major Mesopotamian kingdoms, alongside Babylonia in the south, and at times became the dominant power in the ancient Near East. The city underwent several periods of foreign rule and domination before Assyria rose under Ashur-uballit I in the 14th century BC as the Middle Assyrian Empire. Centered in the Assyrian heartland in northern Mesopotamia, Assyrian power fluctuated over time. 2600 BC but there is no evidence that the city was independent until the collapse of the Third Dynasty of Ur in the 21st century BC, when a line of independent kings beginning with Puzur-Ashur I began ruling the city. Assur, the first Assyrian capital, was founded c.
AD 240) periods, based on political events and gradual changes in language. Spanning from the early Bronze Age to the late Iron Age, modern historians typically divide ancient Assyrian history into the Early Assyrian ( c. Assyria ( Neo-Assyrian cuneiform:, romanized: māt Aššur Classical Syriac: ܐܬܘܪ, romanized: ʾāthor) was a major ancient Mesopotamian civilization which existed as a city-state from the 21st century BC to the 14th century BC and then as a territorial state and eventually an empire from the 14th century BC to the 7th century BC.