Diman introduces the vestiges as a new nominal scene, while “tajarrama ... ḥijaj” specifies the elapsed years. Ḥijaj is the subject of the verb of passing, and “after the time of their inhabitants” supplies the historical reference point.
Ḥalāluhā wa-ḥarāmuhā refers to categories of months, not to the dwellings being legally permitted or forbidden. The paired terms make the passage of entire annual cycles vivid.