Simplify the following text for a Grade 10 native English-speaking person.
Original: Successive administrations tried to stabilize the imperial economy by freezing the social structure into place : sons were to succeed their fathers in their trade , councillors were forbidden to resign , and coloni , the cultivators of land , were not to move from the land they were attached to .
Simplified: Councillors were forbidden to resign , and coloni , the cultivators of land , were not to move from the demesne they were attached to .