The next year he became engaged in political controversy, which resulted in the production of his most famous work. Charles II was without a legitimate child, and the heir to the throne was his brother, the Duke of York, who a few years later actually became king as James II. But while Charles was outwardly, for political reasons, a member of the Church of England (at heart he was a Catholic), the Duke of York was a professed and devoted Catholic, and the powerful Whig party, strongly Protestant, was violently opposed to him. The monstrous fiction of a 'Popish Plot,' brought forward by Titus Oates, and the murderous frenzy which it produced, were demonstrations of the strength of the Protestant feeling, and the leader of the Whigs, the Earl of Shaftesbury, proposed that the Duke of York should be excluded by law from the succession to the throne in favor of the Duke of Monmouth, one of the king's illegitimate sons. At last, in 1681, the nation became afraid of another civil war, and the king was enabled to have Shaftesbury arrested on the charge of treason. Hereupon Dryden, at the suggestion, it is said, of the king, and with the purpose of securing Shaftesbury's conviction, put forth the First Part of 'Absalom and Achitophel,' a masterly satire of Shaftesbury, Monmouth, and their associates in the allegorical disguise of the (somewhat altered) Biblical story of David and Absalom. [Footnote: The subsequent history of the affair was as follows: Shaftesbury was acquitted by the jury, and his enthusiastic friends struck a medal in his honor, which drew from Dryden a short and less important satire, 'The Medal.' To this in turn a minor poet named Shadwell replied, and Dryden retorted with 'Mac Flecknoe.' The name means 'Son of Flecknoe,' and Dryden represented Shadwell as having inherited the stupidity of an obscure Irish rimester named Flecknoe, recently deceased. The piece is interesting chiefly because it suggested Pope's 'Dunciad.' Now, in 1682, the political tide again turned against Shaftesbury, and he fled from England. His death followed shortly, but meanwhile appeared the Second Part of 'Absalom and Achitophel,' chiefly a commonplace production written by Nahum Tate (joint author of Tate and Brady's paraphrase of the Psalms into English hymn-form), but with some passages by Dryden.]