Paradise Lost is a covert account of the ageing Milton's response to the momentous historical events in which he had played such an active and uncompromising part: English revolution.
Milton was famous throughout western Europe for his justifications of the execution of King Charles I. Many people were like Milton in disapproving of the increasingly ceremonial high manner in which the church was being to run.
Milton was a puritan and desired a simplifying the forms of worship between the individual believer and God. His confession of commitment to Purtianism was seen in Lycidas (1637) which was an attack on bishops whom Milton thought were causing such harm. Three years later, Milton attacked the very idea of a bishop at length in his anti-episcopal tracts.
In 1640's, Milton argued with the Church over the censorship in the church which forced many authors and works underground and resulted in violent punishment of others.
This is found in Areopagitica which was named after an ancient council in Athens which argued for widespread press freedom that constantly affirms the benefits of permitting people the responsibility to choose between good and evil.
Milton also argued for fundamental changes in the law of marriage. The divorce tracts forced a contradictory awareness between an intense idealisation of female beauty and companionship with a general patriarchial despising of female ability, a conflict which provides its later poetry with so much of its energy and lack of resolution.
Contrast between the allegory of the birth of Death from Sin and Death's rape of his mother in PL Bk 2 with the description of Eve in Bk 4. Beauty is used to point up her frailty until she is effectively blamed for the Fall of Mankind.
Words as sinews
In PL, Milton chooses to abandon rhyme (which he regarded as a personal and political 'bondage') and deliberately ran sentences over lines, to create that 'sinuous' syntax which he thought so necessary for his own language. Milton viewed language in this way as he had been trained in the classical arts of eloquence, oratory and rhetoric.
Rhetoric revived in Renaissance Europe under largely monarchial regimes, origins were in the political ideal of the ancient republican city states, where the requirements of citizenship were fulfilled by virtuous public speaking.
Classical literature showed Milton that kings usually degenerated into tyrants. This was the opinion of Aristotle and in Greek and Roman tragedies, kingly tyranny was exposed at its worst. The only true King is the King Jesus in heave and that the best kind of kingship on earth is the capacity for self-control.
Having punished England once with the Civil War for an unreformed church, God was now punishing England again, for the policies of the 1650s. In Bk 2 the parliament in Hell can be seen as a reflection of Milton's disillusionment with secular republicanism as the speeches of Satan etc. are just piles of fucking shit. Also seen to be disparaging of language of republicanism.