Simplify the following text for a Grade 12 native English-speaking person.
Original: The cities of Norsuntepe , Emar and Carchemish were destroyed , Assyria lost northwestern cities to Mushki , which were reconquered by Tiglath-Pileser I after his ascension to kingship .
Simplified: Several cities were destroyed , Assyria lost northwestern cities which were reconquered by Tiglath-Pileser I after his ascension to kingship .