Comedy, being based on the fluctuating circumstances of real life, lends itself more easily than tragedy to a change of form. Hence, while tragic art after once passing its prime slowly but steadily declines, comedy seems endued with greater vitality, and when politics and religion are closed to it, readily contents itself with the less ambitious sphere of manners. Thus, at Athens, Menander raised the new comedy to a celebrity little if at all inferior to the old; while the form of art which he created has retained its place in modern literature as perhaps the most enduring which the drama has assumed. In Rome there was far too little liberty of speech for the Aristophanic comedy to be possible. Outspoken attacks in public on the leading statesmen did not accord with the senatorial idea of government. Hence such poets as possessed a comic vein were driven to the only style which could be cultivated with impunity, viz. that of Philemon and Menander. But a difficulty met them at the outset. The broad allusions and rough fun of Aristophanes were much more intelligible to a Roman public than the refined criticism and quiet satire of Menander, even supposing the poet able to reproduce these. The author who aspired to please the public had this problem before him,--while taking the Middle and New Comedy of Athens for his model, to adapt them to the coarser requirements of Roman taste and the national rather than cosmopolitan feeling of a Roman audience, without drawing down the wrath of the government by imprudent political allusions. It was the success with which Plautus fulfilled these conditions that makes him pre-eminently the comic poet of Rome; and which, though purists affected to depreciate him, [10] excited the admiration of such men as Cicero, [11] Varro, and Sisenna, and secured the uninterrupted representation of his plays until the fourth century of the Empire.