The history of the unity of time during the next century does not strictly concern us here; but it may be well to point out that it was through the offices of Chapelain, seconded by the authority of Cardinal Richelieu, that it became fixed in the dramatic theory of France. In a long letter, dating from November, 1630, and recently published for the first time, Chapelain sets out to answer all the objections made against the rule of twenty-four hours. It is sustained, he says, by the practice of the ancients and the universal consensus of the Italians; but his own proof is based on reason alone. It is the old argument of _vraisemblance_, as found in Maggi, Scaliger, and especially Castelvetro, whom Chapelain seems in part to follow. By 1635 he had formulated the whole theory of the three unities and converted Cardinal Richelieu to his views. In the previous year Mairet's _Sophonisbe_, the first "regular" French tragedy, had been produced. In 1636 the famous _Cid_ controversy had begun. By 1640 the battle was gained, and the unities became a part of the classic theory of the drama throughout Europe. A few years later their practical application was most thoroughly indicated by the Abbe d'Aubignac, in his _Pratique du Theatre_; and they were definitely formulated for all time by Boileau in the celebrated couplet:-- "Qu'en un lieu, qu'en un jour, un seul fait accompli Tienne jusqu'a la fin le theatre rempli."[374] III. _Heroic Poetry_ It was the supreme ambition of the Pleiade to produce a great French epic. In the very first manifesto of the new school, Du Bellay urges every French poet to attempt another _Iliad_ or _AEneid_ for the honor and glory of France. For Pelletier (1555) the heroic poem is the one that really gives the true title of poet; it may be compared to the ocean, and all other forms to rivers.[375] He seems to be following Giraldi Cintio's discourse on the _romanzi_, published the year before his own work, when he says that the French poet should write a _Heracleid_, the deeds of Hercules furnishing the mightiest and most heroic material he can think of.[376] At the same time Virgil is for him the model of an epic poet; and his parallel between Homer and Virgil bears striking resemblance to the similar parallel in Capriano's _Della Vera Poetica_, published in the very same year as his own treatise.[377] Like Capriano, Pelletier censures the superfluous exuberance, the loquaciousness, the occasional indecorum, and the inferiority in eloquence and dignity of Homer when compared with the Latin poet.