Re separation of Powers:
John Fortescue (c. 1394–1479) was chief justice of Britain’s high court and his classic In Praise of the Laws of England . Fortescue held there that the English constitution limited the powers of the monarch under the traditional laws of England
in the same way that the powers of the Jewish king in the Mosaic constitution in Deuteronomy are limited by the traditional laws of the Israelite nation. This is in contrast with the Holy Roman Empire of Fortescue’s day, which was supposedly governed by Roman law, and therefore by the maxim that ‘what pleases the prince has the force of law,’ and in contrast with the kings of France, who governed absolutely.
Fortescue laid out “what later tradition would call the separation of powers and the system of checks and balances.” He linked “the character of a nation’s laws and their protection of private property to economic prosperity, arguing that limited government bolsters such prosperity, while an absolute government leads the people to destitution and ruin.” His work, adds Hazony and Haivry
“the belief that through long centuries of experience, and thanks to a powerful ongoing identification with Hebrew Scripture, the English had succeeded in creating a form of government more conducive to human freedom and flourishing than any other known to man.”
the 17th century jurists John Selden,
Hugo Grotious expounded further on this