倒装的问题

(From Christianity and the barbarian kingdoms of the west) 地点状语
emerged 谓语
the medieval version of politics 主语
from which in turn evolved the politics of our modern world. 定语从句,修饰主语

from which in turn evolved the politics of our modern world.这个从句中:
from which 介词+关系代词作状语
in turn 词组状语
evolved 谓语
the politics of our modern world 主语

意思是:从基督教和西方的野蛮王国中出现了中世纪政治的形态,这种形态的政治又演变成了现代的政治.

正常语序几乎是不可能的,可以分成2句话:

the medieval version of politics emerged from Christianity and the barbarian kingdoms of the west

the politics of our modern world in turn evolved from the medieval version of politics.

the medieval version of politics from which...world是本来的主语。原句整句是倒装的。正常语序：
The medieval version of politics from which in turn evolved the politics of our modern world emerged from Christianity and the barbarian kingdoms of the west.
倒装的原因是为了强调：from Christianity and the barbarian kingdoms of the