Strangely enough, it was priest-ridden Spain that all through the sixteenth and seventeenth centuries led the van of revolt against the rules and precepts of the grammarians. While Torquato Tasso remained the miserable slave of grammarians unworthy to lick the dust from his feet, Lope de Vega slyly remarked that when he wrote his comedies, he locked up the givers of precepts with six keys, that they might not reproach him. J.B. Marino declared that he knew the rules better than all the pedants in the world; "but the true rule is to know when to break the rules, in accordance with the manners of the day and the taste of the age." Among the most acute writers of the end of the seventeenth century is to be mentioned Gravina, who well understood that a work of art must be its own criterion, and said so clearly when praising a contemporary for a work which did not enter any one of the admitted categories. Unfortunately Gravina did not clearly formulate his views. France of the eighteenth century produced several writers like Du Bos, who declared that men will always prefer the poems that move them, to those composed according to rule. La Motte combated the unities of place and time, and Batteux showed himself liberal in respect to rules. Voltaire, although he opposed La Motte and described the three unities as the three great laws of good sense, was also capable of declaring that all styles but the tiresome are good, and that the best style is that which is best used. In England we find Home in his _Elements of Criticism_ deriding the critics for asserting that there must be a precise criterion for distinguishing epic poetry from all other forms of composition. Literary compositions, he held, melt into one another, just like colours. The literary movement of the end of the eighteenth and the beginning of the nineteenth centuries attacked rules of all sorts. We will not dwell upon the many encounters of these periods, nor record the names of those that conquered gloriously, or their excesses. In France the preface to the _Cromwell_ of V. Hugo (1827), in Italy the _Lettera semiseria di Grisostomo_, were clarions of rebellion. The principle first laid down by A.W. Schlegel, that the form of compositions must be organic and not mechanic, resulting from the nature of the subject, from its internal development not from an external stamp, was enunciated in Italy. Art is always a whole, a synthesis.