בראשית, פרק י׳, פסוק י״א

Following the establishment of the first kingdoms in the Babylonian region, a significant movement of migration and urban expansion took place. The identity of the leader behind this expansion is left ambiguous, leading to two main interpretations. The primary approach among commentators is that the narrative continues to focus on Nimrod and the growth of his empire. According to this view, Nimrod departed from his original stronghold in Babylon, invaded the region of Assyria, and constructed fortified cities there after the construction of the Tower of Babel came to a halt [מלבי״ם]. Because the destination is understood as the land of Assyria rather than a person [רמב״ן, שד״ל, חזקוני, בכור שור, ביאור יש״ר, קאסוטו], this explains why later prophets refer to Assyria as the land of Nimrod [רמב״ן, קרני אור, אם למקרא].

In contrast, a broad interpretive tradition understands the text literally, identifying Asshur not as a place, but as a person—one of the sons of Shem. In this reading, Asshur chose to distance himself both physically and ideologically from Nimrod's tyrannical rule and the sinful rebellion against God during the generation of the dispersion, prompting him to leave the area entirely [רש״י, רבנו בחיי, הדר זקנים, תולדות יצחק, נתינה לגר]. While Nimrod sought greatness through violent conquest and political dominance, Asshur found his purpose in positive development and building infrastructure [רש״ר הירש, ביאור שטיינזלץ]. As a reward for refusing to participate in the rebellion against God, Asshur was granted the privilege of building these great cities [ספורנו]. Within this perspective, there are varying opinions regarding the dynamics between the two leaders. Some suggest Asshur did not rebel openly but left with Nimrod's permission to build nearby settlements [העמק דבר]. Others propose a power struggle occurred, resulting either in Asshur defeating Nimrod for the throne, or Asshur ruling the region first before Nimrod eventually invaded [רד״ק, מחוקקי יהודה].

The act of building these cities can be understood either as establishing entirely new settlements from the ground up or as restoring and fortifying cities that had previously been destroyed [קאסוטו]. The first city established was Nineveh, which would eventually become the central and largest city of the Assyrian empire, located along the Tigris River [ביאור שטיינזלץ, קאסוטו]. According to the view that Nimrod was the builder, he may have named the city after his son, combining the words for "son" and "dwelling" [אם למקרא].

The expansion continued with Rehoboth-ir. Some explain this was the specific name of the city, with the word for "city" appended to clarify that it was a proper settlement rather than just a collection of streets [שד״ל]. Other commentators suggest that as Nineveh's population rapidly increased, suburbs, neighborhoods, and wide streets were constructed around it to accommodate the growing masses, and this sprawling metropolitan addition became known as Rehoboth-ir [מלבי״ם, קאסוטו]. Additionally, early sages identify this location as a specific area enriched by the waters of the Euphrates River [תורה תמימה]. Finally, Calah was built as an important city south of Nineveh, likely serving as another practical solution to overcrowding and the ongoing need for territorial expansion [מלבי״ם, קאסוטו].