Simplify the following text for a Grade 9 native English-speaking person.
Original: He is famous for his articulation of the theory of separation of powers , taken for granted in modern discussions of government and implemented in many constitutions throughout the world .
Simplified: He lived during the Enlightenment , and is famous for his theory of separation of powers ; This theory is taken for granted in modern discussions of government . Many constitutions all over the world use it .