The title of Milton's Areopagitica alludes to both the Areopagiticus of Isocrates and the story of the apostle Paul in Athens from Acts 17: 18-34. Isocrates' tract, which outlines a program for political reform, specifically mentions the degradation of the judges of the Court of the Areopagus, the highest court in Greece. Milton may fancy himself a man similar in virtue and sagacity to the old judges of the Areopagus whom Isocrates praises; following this allusion, the morally weakened judges of the Areopagus are made to stand for England's sitting Parliament. Milton doubly identifies with the voice of reform and the sober-minded leaders of a previous generation. The allusion to Paul in the Book of Acts contains a similar parallel: Paul preaches to the pagan Athenians at the Areopagus (the hill where the judges once sat). In his appeal to the Athenians, Paul uses a stock phrase from a poem by Aratus, with whom the Greeks would certainly have been familiar. Paul leverages his knowledge of pagan poetry and religion to instruct the Athenians about Christianity.
Milton divides his scholarly affections between the classical and the biblical in Areopagitica. Notice, though, that in this speech classical allusions outweigh biblical, particularly in the first half of the tract. Milton seems to be making an attempt, by way of copious example, to demonstrate just how Greek and Roman learning can be used to advantage within the boundaries of Christian morality, even doctrine. At first, one might be inclined to dismiss this as merely Milton's attempt to reconcile the differences between his two intellectual loves. But a closer examination of Areopagitica will reveal Milton's more cagey purpose for allowing classical references to dominate. It is a subtle attempt to flatter members of Parliament, by comparing their commonwealth to the enlightened societies of Athens and Rome. By leveraging the vanity of English politicians, who would of course like to think of themselves as the senators of a latter-day Athens or Rome, Milton hopes to change their minds about a licensed press. Only an ignorant man would criticize the policies of Athens, and that city, as Milton argues, did not support the licensing of books. Milton seems to express a faith that England's enlightened leaders would never embark on a policy that would demonstrate their country's inferiority to those ancient societies.
Milton's tract is a direct response to the the Licensing Order of 1643 which reinstated much the same sort of pre-publication censorship once exercised by the Star Chamber and other earlier censors, royal and ecclesiastical. Milton does not argue here for free and unregulated speech or printing, but simply that books should not be suppressed before publication. Treasonous, slanderous and blasphemous books, he allows, should be tried according to law, then suppressed and their authors punished.
The counter-examples Milton offers to those enlightened societies of Greece and Rome are the tyrannical societies of Catholic Spain and the Inquisition. Milton offers the members of Lords and Commons a clear choice: either abolish censorship or stand in imitation of Popery. By making the counter-example to enlightened policy Catholicism, Milton once again demonstrates an acute understanding of his audience. Parliament during Milton's time, especially the House of Commons, was energetically anti-Catholic. The thought that any of their orders might have an odor of unreformed Popery about it was distasteful, especially during the particularly tumultuous days surrounding the civil wars. Areopagitica demonstrates Milton to be not only a great wordsmith and scholar, but also a brilliant political orator, even though this address to Parliament was never delivered orally.
Milton's Areopagitica had virtually no political impact in its day: Parliament ignored it. However, as the first major treatise on press freedom, it influenced the arguments of many later advocates for the abolition of censorship. Even the United States Bill of Rights can be viewed as a direct descendent of Milton's Areopagitica. Part of the reason that it was ignored in its day may be that Milton had already challenged Parliament and popular opinion with other unorthodox arguments, such as the one presented in the Doctrine and Discipline of Divorce and its defenses (Tetrachordon, Colasterion). Though he attempted to cultivate an image as a gentleman poet, Milton held radical opinions which challenged societal norms and was even accused of heresy by some of his rivals and targets. In Areopagitica we have a prime example of the nature of Milton's genius: heavily inflected with biblical and classical knowledge, but too unorthodox for mainstream acceptance, at least in his day.