Assyria was a major Mesopotamian kingdom and empire of the ancient Near East and the Levant. It existed as a state from perhaps as early as the 25th century BC in the form of the Assur city-state, until its lapse between 612 BC and 599 BC, spanning the Early to Middle Bronze Age through to the late Iron Age. From the end of the seventh century BC to the mid-seventh century AD, it survived as a geopolitical entity, for the most part ruled by foreign powers, although a number of Neo-Assyrian states arose at different times during the Parthian and early Sasanian Empires between the mid-second century BC and late third century AD, a period which also saw Assyria become a major centre of Syriac Christianity and the birthplace of the Church of the East. 

Centered on the Tigris in Upper Mesopotamia (modern northern Iraq, northeastern Syria, southeastern Turkey and the northwestern fringes of Iran), the Assyrians came to rule powerful empires at several times. Making up a substantial part of the greater Mesopotamian "cradle of civilization", which included Sumer, the Akkadian Empire, and Babylonia, Assyria was at the height of technological, scientific and cultural achievements for its time. At its peak, the Assyrian empire stretched from Cyprus and the East Mediterranean to Iran, and from what is now Armenia and Azerbaijan in the Caucasus, to the Arabian Peninsula, Egypt and eastern Libya.
where did the kingdom stretch to?
from Cyprus and the East Mediterranean to Iran, and from what is now Armenia and Azerbaijan in the Caucasus, to the Arabian Peninsula, Egypt and eastern Libya.