Proper noun
Subartu
A region of upper Mesopotamia in the Bronze Age, which later came to be called Assyria.
Elam and the northern part of Mesopotamia ( Assyria Subartu ) were also subjugated, and rebellions in Sumer were put down. Source: Internet
Similarly, in c. the early 25th century BC, Lugal-Anne-Mundu the king of the Sumerian state of Adab lists Subartu as paying tribute to him. Source: Internet