and concluded that certain truth could not be known by man[86]. He pressed Zeno closely as to his definition of ‘comprehension,’ and induced him to add a clause which, in the opinion of his opponent, shewed the worthlessness of the whole doctrine[87]. Thus was raised the question of the κριτήριον or test of truth, which for at least a century to come sharply divided the schools[88]. [Sidenote: Zeno at Athens.] =85.= The conflict between these three schools, which from this time on greatly surpassed all others in importance, did not embitter the political life of Athens. The citizens watched with amusement the competition of the schools for numbers and influence, and drew their profit from the crowds of foreigners who were drawn to Athens by its growing fame as a centre of adult education. To the heads of the schools they were ready to pay every mark of respect. With Zeno they deposited the keys of their gates, and they awarded him during his lifetime a gold crown and a bronze statue. His fame spread abroad, and those of his fellow-citizens of Citium who were then resident at Sidon claimed a share in it. In his old age the high-minded Antigonus Gonatas (who occupied the throne of Macedonia with varying fortune from 278 to 239 B.C.) looked to him for advice and help. But no offers of public employment could draw Zeno himself from his simple life and the young companions who surrounded him: like Socrates, he thought that he could best serve the State by sending out others to take part in its duties[89]. He died in the year 264 B.C.[90], having been engaged in teaching for more than 30 years from the time when he ‘discovered the truth[91].’ [Sidenote: Honours paid to him.] =86.= The vote which the Athenians passed in honour of Zeno, shortly before his death, deserves record by its contrast with that by which their predecessors had condemned Socrates. It ran somewhat as follows: ‘Whereas Zeno the son of Mnaseas from Citium has spent many years in this city in the pursuit of philosophy; and has been throughout a good man in all respects; and has encouraged the young men who resorted to him in virtue and temperance, and has sped them on the right path; and has made his own life an example to all men, for it has been consistent with the teaching he has set forth;