From the fourteenth century Cicero was recognised universally as the purest model of prose. This was by no means due solely to a dispassionate opinion in favour of his choice of language, of the structure of his sentences, and of his style of composition, but rather to the fact that the Italian spirit responded fully and instinctively to the amiability of the letter-writer, to the brilliancy of the orator, and to the lucid exposition of the philosophical thinker. Even Petrarch recognised clearly the weakness of Cicero as a man and a statesman,[589] though he respected him too much to rejoice over them. After Petrarch’s time, the epistolary style was formed entirely on the pattern of Cicero; and the rest, with the exception of the narrative style, followed the same influence. Yet the true Ciceronianism, which rejected every phrase which could not be justified out of the great authority, did not appear till the end of the fifteenth century, when the grammatical writings of Lorenzo Valla had begun to tell on all Italy, and when the opinions of the Roman historians of literature had been sifted and compared.[590] Then every shade of difference in the style of the ancients was studied with closer and closer attention, till the consoling conclusion was at last reached, that in Cicero alone was the perfect model to be found, or, if all forms of literature were to be embraced, in ‘that immortal and almost heavenly age of Cicero.’[591] Men like Pietro Bembo and Pierio Valeriano now turned all their energies to this one object. Even those who had long resisted the tendency, and had formed for themselves an archaic style from the earlier authors,[592] yielded at last, and joined in the worship of Cicero. Longolius, at Bembo’s advice, determined to read nothing but Cicero for five years long, and finally took an oath to use no word which did not occur in this author. It was this temper which broke out at last in the great war among the scholars, in which Erasmus and the elder Scaliger led the battle.