Shamshi-Adad I did not return until retaking Ekallatum, pausing for some time, and then overthrowing King Erishum II of Assur (fl.

In keeping with this assumption, scholars have inferred that the original form of the AKL had been written (among other things) as an "attempt to justify that Shamshi-Adad I was a legitimate ruler of the city-state Assur and to obscure his non-Assyrian antecedents by incorporating his ancestors into a native Assyrian genealogy".

Stone tablets with Akkadian inscriptions (formatted in three columns and one hundred and thirty-five lines, from Shamshi-Adad I) have been found near the temple of the god Assur.

He outlined the market prices of that time as being one shekel of silver being worth two kor(gur-cube)s of barley, fifteen minas of wool, or two seahs of oil.

Shamshi-Adad I took over the long-abandoned town of Shekhna (today known as Tell Leilan), converted it into the capital city of the Kingdom of Upper Mesopotamia, and then renamed it Šubat-Enlil (meaning "the residence of the god Enlil" in the Akkadian language)[10] c. 1808 BC.

[12] A main target for expansion was the city of Mari, which controlled the caravan route between Anatolia and Mesopotamia.

On inscriptions Shamshi-Adad I boasts of erecting triumphal stelae on the coast of the Mediterranean Sea, but these probably represent short expeditions rather than any attempts at conquest.

His campaigns were meticulously planned, and his army knew all the classic methods of siegecraft, such as encircling ramparts and battering rams.

[6] Shamshi-Adad I sent a letter on a tablet to Ishi-Addu (Beltum's father, the King of Qatna) in which he discussed their alliance, the attacks of their enemies, and the successful marriage between their children.

In it Shamshi-Adad I wrote: "I heard that you gladly dispatched my daughter-in-law on a safe way back to me, that you treated my servants when they stayed with you well, and that they were not hindered at all.

"[15]Shamshi-Adad I was a great organizer and he kept firm controls on all matters of state, from high policy down to the appointing of officials and the dispatching of provisions.

The local rulers of the city Qattara maintained authority (but became vassals) when they were incorporated into the Kingdom of Upper Mesopotamia.

[6] Shamshi-Adad I continued to strengthen his kingdom throughout his life, but as he got older, the state became more vulnerable and the neighboring great powers Yamkhad and Eshnunna began attacking.

Naturally, Shamshi-Adad I's rise to glory earned him the envy of neighboring kings and tribes, and throughout his reign, he and his sons faced several threats to their control.