פּירוש אויף בראשית 10:10

ותהי ראשית ממלכתו וגו, “at the beginning his kingdom extended only to Babylonia and Accadia, extending eventually throughout the whole region of Shinor. Eventually he even conquered the region of Ashur. (northeast) Ashur had emigrated as he could not stand Nimrod’s antiG-d attitude.

ותהי ראשית, first he conquered Babylon, and established himself as king there. Subsequently, he conquered ארך, אכד, and כלנה, all of which are part of the land known as the land of Shinor. After that he went on to conquer many more and more distant lands.

ותהי ראשית ממלכתו בבל, the Torah mentions this to explain that because of Nimrod’s powerful and relatively civilised kingdom all the people moved to the valley of Shinor to be within the orbit of his power and influence. The illusion of great power, augmented by unity of purpose, led to their insurrection against G’d, and to their downfall. Central symbols always exercised a gravitational pull on people’s minds, as we see even among the Jewish people in the efforts by Jerobam to counteract the centrality of the Temple in Jerusalem. (Kings I 12,26)