What historians call the degree to which people
can move up or down in a society?

Structural Mobility

Explanation:

Structural mobility happens when societal changes enable a whole group of people to move up or down the social class ladder.

explanation:

damn girl thats not really your friend then. : /

the church governed the society after the empire fell.   constantine took charge of rome and ended the confusion which had over religion and made christianity as the only religion and that started ruling the roman empire. he also divided the empire into two and fortified the eastern part.   he ruled the eastern part.