Sin-shumu-lishir was a usurper

Usurper

Usurper is a derogatory term used to describe either an illegitimate or controversial claimant to the power; often, but not always in a monarchy, or a person who succeeds in establishing himself as a monarch without inheriting the throne, or any other person exercising authority unconstitutionally...

 king

Kings of Assyria

The list of Assyrian kings is compiled from the Assyrian King List, an ancient kingdom in northern Mesopotamia with information added from recent archaeological findings. The Assyrian King List includes regnal lengths that appear to have been based on now lost limmu lists...

 of a part of the Assyria

Assyria

Assyria was a Semitic Akkadian kingdom, extant as a nation state from the mid–23rd century BC to 608 BC centred on the Upper Tigris river, in northern Mesopotamia , that came to rule regional empires a number of times through history. It was named for its original capital, the ancient city of Assur...

n empire during 626 BC. Little is known about this king due to the lack of sources covering this time.

Reign

Sin-shumu-lishir first appears in Assyrian sources as a general of the Assyrian king Ashur-etil-ilani

Ashur-etil-ilani

Ashur-etil-ilani was a king of Assyria . He succeeded his father Ashurbanipal.- Problems with source material :The reconstruction of the events occurring during Ashur-etil-ilani's rule has proven to be very difficult...

. It seems that he later tried to seize the throne. He is credited with a reign of one year by the Uruk

Uruk

Uruk was an ancient city of Sumer and later Babylonia, situated east of the present bed of the Euphrates river, on the ancient dry former channel of the Euphrates River, some 30 km east of modern As-Samawah, Al-Muthannā, Iraq.Uruk gave its name to the Uruk...

 king list, preceding Sin-shar-ishkun

Sinsharishkun

Sinsharishkun , who seems to have been the Saràkos of Berossus, was one of the last kings of the Assyrian empire.-Early years:...

.

His first year was attested in texts from the Babylonian cities of Bab-ili

Babylon

Babylon was an Akkadian city-state of ancient Mesopotamia, the remains of which are found in present-day Al Hillah, Babil Province, Iraq, about 85 kilometers south of Baghdad...

, Nippur

Nippur

Nippur was one of the most ancient of all the Sumerian cities. It was the special seat of the worship of the Sumerian god Enlil, the "Lord Wind," ruler of the cosmos subject to An alone...

, and Ru'a. Because there is only evidence about his first year as ruler, it is not likely that his reign lasted much longer. Sin-shumu-lishir never controlled all of the Assyrian empire and most likely only a part of Babylonia

Babylonia

Babylonia was an ancient cultural region in central-southern Mesopotamia , with Babylon as its capital. Babylonia emerged as a major power when Hammurabi Babylonia was an ancient cultural region in central-southern Mesopotamia (present-day Iraq), with Babylon as its capital. Babylonia emerged as...

.

His short reign must have taken place in 626 BC because before that year Kandalanu

Kandalanu

- Territory :Kandalanu was king over Babylonia, with exception of the city Nippur. His reign began in 648 B.C. when he was appointed by his overlord King Ashurbanipal of Assyria after the latter had crushed the Babylonian rebellion by Kandalanu’s predecessor, Shamash-shum-ukin.- Identity :Because...

 reigned over his attested cities and after that Nabopolassar

Nabopolassar

Nabopolassar was the king of the Babylonia and played a key role in the demise of the Assyrian Empire following the death of the last powerful Assyrian king, Ashurbanipal...

 and Sinsharishkun

Sinsharishkun

Sinsharishkun , who seems to have been the Saràkos of Berossus, was one of the last kings of the Assyrian empire.-Early years:...

did so.